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All COVID Emails (so Far) From Chris Masterjohn
- Thread starter RealNeat
- Start date
Ok here goes...
This is the first COVID-19 research update! Actually if you look at the archive, I included a post I originally made on Facebook and Twitter the other day as the first update, but this is the first one I'm writing directly to the list.
The reason I'm interested in hydroxychloroquine and chloroquine is many people are claiming that these are effective against the coronavirus because they help bring zinc into cells, and the zinc kills the virus, and others have argued that since quercetin and EGCG do the same thing, these also would be effective for prevention or treatment of the coronavirus. If quercetin or EGCG should be effective in this way, I would want to add them to the protocol I use in The Food and Supplement Guide for the Coronavirus.
The first step, then, was to figure out if hydroxychloroquine or chloroquine are actually effective.
Chloroquine is a drug long used to treat malaria. Hydroxychloroquine is a closely related compound that has also been used to treat malaria, but more recently has been used to treat autoimmune conditions such as lupus and rheumatoid arthritis.
More recently these drugs have been shown in vitro (in a test tube, not a living organism) to have a broad spectrum of antiviral activities. Although they have never been shown to have clear antiviral activity in humans against any virus, they have become widely used in China to treat COVID-19.
The potential of these drugs to treat COVID-19 received a lot of hype from Donald Trump recently. As a result, out of fear of the virus and hype over chloroquine, a Phoenix man and his wife drank a fish tank cleaner containing chloroquine phosphate. The man died and the wife wound up in critical care.
Is the hype deserved?
As reviewed in "Of Chloroquine and COVID-19,"
That the expert opinion was running far ahead of the data is demonstrated in this quote from the paper:
A narrative letter by Chinese authors reported that a news briefing from the State Council of China had indicated that “Chloroquine phosphate… had demonstrated marked efficacy and acceptable safety in treating COVID-19 associated pneumonia in multicentre clinical trials conducted in China.” The authors also stated that these findings came from “more than 100 patients” included in the trials. We sought for evidence of such data in the trial registries we reviewed and found none.
As I reviewed the other day, a non-randomized French trial of hydroxychloroquine suggested the drug virologically cured 15 out of 26 people, while it nauseated one, put three in ICU, and killed one. Because it wasn't randomized, it isn't clear whether the cure or the worsening represent true effects of the drug, but if we are to regard the cure as a real effect, we also have to regard the worsening as a real effect, suggesting that if it works it might have a high risk profile.
A Chinese randomized controlled trial found no difference at all between the use of hydroxychloroquine and standard treatment. The standard treatment was bed rest, oxygen inhalation, symptomatic support, neubulized interferon, lopinavir and ritonavir (two antivirals), and, when necessary, antibacterials. The two antivirals in the standard treatment have also been shown to have no effect against another "standard treatment" in another randomized trial (hat tip to Avi for this study). In that trial, the standard care was supplemental oxygen, ventilation, antibiotic agents, vasopressor support, renal-replacement therapy, and extracorporeal membrane oxygenation (ECMO). So, none of the antivirals did anything beyond the oxygen therapy and other support in the list.
The World Health Organization is launching a multinational set of trials testing the efficacy of interferon, chloroquine, lopinavir, and ritonavir. This should provide us with some information, but right now a lot of things are being thrown at COVID-19 with no clear evidence they are effective.
That WHO is launching this trial should also help allay rational fears that Chinese data can't be trusted. After all, China just expelled all the American journalists, so it's clear the Chinese government doesn't value transparency around the COVID-19 situation.
So, are hydroxychloroquine or chloroquine effective?
I'd bet it at 50/50 odds, at best. Hyping them as saviors is nuts.
I also find it ironic that many people will beat the "trust the experts" drum endlessly, bashing anyone suggesting nutrients or herbs could be relevant, yet vitamin D, elderberry, and garlic have all been shown to have antiviral effects in humans, yet hydroxychloroquine and chloroquine have not. Why do these drugs get special status just because the experts are using them with no evidence of their efficacy?
In any case, what, if anything does this say about quercetin? I'll let you know over the next couple of days.
Stay safe,
Chris
PS. If someone forwarded this to you, or you just joined the list without really knowing much about me, and you are wondering who I am or what my credentials are, you can read more about me here.
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PPPS. This email may contain affiliate links, which earn me commissions if you purchase products, at no extra cost to you. You can read my full affiliate disclosure here.
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PPPPPS. If you received this directly, you are currently subscribed to my occasional newsletter. This is not my list for content updates. If you are already subscribed to my newsletter and want to *also* receive an email update every time content is posted to my site, click here: Subscribe me to content updates too! Or if you don't want to add notifications about everything but do want to add notifications for my short, practical tips twice a week, click here: Subscribe me to Chris Masterjohn Lite too!. Or if you don't want to add notifications about everything but do want to add notifications for my once-a-week long-form podcasts, click here: Subscribe me to Mastering Nutrition too!. If you are already on other lists of mine and you want to stay on those but get *off* of this list, use this link: Unsubscribe me ONLY from this newsletter.
This is the first COVID-19 research update! Actually if you look at the archive, I included a post I originally made on Facebook and Twitter the other day as the first update, but this is the first one I'm writing directly to the list.
The reason I'm interested in hydroxychloroquine and chloroquine is many people are claiming that these are effective against the coronavirus because they help bring zinc into cells, and the zinc kills the virus, and others have argued that since quercetin and EGCG do the same thing, these also would be effective for prevention or treatment of the coronavirus. If quercetin or EGCG should be effective in this way, I would want to add them to the protocol I use in The Food and Supplement Guide for the Coronavirus.
The first step, then, was to figure out if hydroxychloroquine or chloroquine are actually effective.
Chloroquine is a drug long used to treat malaria. Hydroxychloroquine is a closely related compound that has also been used to treat malaria, but more recently has been used to treat autoimmune conditions such as lupus and rheumatoid arthritis.
More recently these drugs have been shown in vitro (in a test tube, not a living organism) to have a broad spectrum of antiviral activities. Although they have never been shown to have clear antiviral activity in humans against any virus, they have become widely used in China to treat COVID-19.
The potential of these drugs to treat COVID-19 received a lot of hype from Donald Trump recently. As a result, out of fear of the virus and hype over chloroquine, a Phoenix man and his wife drank a fish tank cleaner containing chloroquine phosphate. The man died and the wife wound up in critical care.
Is the hype deserved?
As reviewed in "Of Chloroquine and COVID-19,"
- "To date, no acute virus infection has been successfully treated by chloroquine in humans." It failed to treat flu or dengue in humans.
- For chronic viruses, the results in HIV have been inconclusive, and the results with hepatitis C have been so slight that it's never become part of a standard protocol.
- Although chloroquine has been shown to be antiviral in vitro against SARS-CoV-2, the cause of COVID-19, it also proved antiviral in vitro against chikungunya virus, yet acted as a proviral in living mice. This might be because it can suppress the immune system and might relate to the effectiveness of hydroxychloroquine as a treatment for autoimmune disorders. Could it also make COVID-19 worse?
- Despite the widespread use of chloroquine and hydroxychloroquine to treat COVID-19, there are as yet no randomized controlled trials clearly showing it is effective.
That the expert opinion was running far ahead of the data is demonstrated in this quote from the paper:
A narrative letter by Chinese authors reported that a news briefing from the State Council of China had indicated that “Chloroquine phosphate… had demonstrated marked efficacy and acceptable safety in treating COVID-19 associated pneumonia in multicentre clinical trials conducted in China.” The authors also stated that these findings came from “more than 100 patients” included in the trials. We sought for evidence of such data in the trial registries we reviewed and found none.
As I reviewed the other day, a non-randomized French trial of hydroxychloroquine suggested the drug virologically cured 15 out of 26 people, while it nauseated one, put three in ICU, and killed one. Because it wasn't randomized, it isn't clear whether the cure or the worsening represent true effects of the drug, but if we are to regard the cure as a real effect, we also have to regard the worsening as a real effect, suggesting that if it works it might have a high risk profile.
A Chinese randomized controlled trial found no difference at all between the use of hydroxychloroquine and standard treatment. The standard treatment was bed rest, oxygen inhalation, symptomatic support, neubulized interferon, lopinavir and ritonavir (two antivirals), and, when necessary, antibacterials. The two antivirals in the standard treatment have also been shown to have no effect against another "standard treatment" in another randomized trial (hat tip to Avi for this study). In that trial, the standard care was supplemental oxygen, ventilation, antibiotic agents, vasopressor support, renal-replacement therapy, and extracorporeal membrane oxygenation (ECMO). So, none of the antivirals did anything beyond the oxygen therapy and other support in the list.
The World Health Organization is launching a multinational set of trials testing the efficacy of interferon, chloroquine, lopinavir, and ritonavir. This should provide us with some information, but right now a lot of things are being thrown at COVID-19 with no clear evidence they are effective.
That WHO is launching this trial should also help allay rational fears that Chinese data can't be trusted. After all, China just expelled all the American journalists, so it's clear the Chinese government doesn't value transparency around the COVID-19 situation.
So, are hydroxychloroquine or chloroquine effective?
I'd bet it at 50/50 odds, at best. Hyping them as saviors is nuts.
I also find it ironic that many people will beat the "trust the experts" drum endlessly, bashing anyone suggesting nutrients or herbs could be relevant, yet vitamin D, elderberry, and garlic have all been shown to have antiviral effects in humans, yet hydroxychloroquine and chloroquine have not. Why do these drugs get special status just because the experts are using them with no evidence of their efficacy?
In any case, what, if anything does this say about quercetin? I'll let you know over the next couple of days.
Stay safe,
Chris
PS. If someone forwarded this to you, or you just joined the list without really knowing much about me, and you are wondering who I am or what my credentials are, you can read more about me here.
PPS. If you would like to contact me and receive a response, please use this page to contact me. Please do not respond to this email.
PPPS. This email may contain affiliate links, which earn me commissions if you purchase products, at no extra cost to you. You can read my full affiliate disclosure here.
PPPPS. Did someone forward this to you? You can subscribe to my newsletter here.
PPPPPS. If you received this directly, you are currently subscribed to my occasional newsletter. This is not my list for content updates. If you are already subscribed to my newsletter and want to *also* receive an email update every time content is posted to my site, click here: Subscribe me to content updates too! Or if you don't want to add notifications about everything but do want to add notifications for my short, practical tips twice a week, click here: Subscribe me to Chris Masterjohn Lite too!. Or if you don't want to add notifications about everything but do want to add notifications for my once-a-week long-form podcasts, click here: Subscribe me to Mastering Nutrition too!. If you are already on other lists of mine and you want to stay on those but get *off* of this list, use this link: Unsubscribe me ONLY from this newsletter.
As I explained yesterday, the reason I'm interested in hydroxychloroquine and chloroquine is because I'm investigating whether these, like quercetin and EGCG, are antiviral by acting as zinc ionophores, in which case I might add quercetin and EGCG to the protocol in The Food and Supplement Guide for the Coronavirus.
A zinc ionophore is a compound that can bring zinc across a cellular membrane, thereby transporting the zinc into the cell, or into a specific location within the cell.
Although chloroquine has been shown to act as a zinc ionophore, I doubt this contributes to its antiviral activity against SARS-CoV, the coronavirus that causes SARS, or SARS-CoV-2, the coronavirus that causes COVID-19.
There are three big reasons for this:
By contrast, chloroquine's antiviral activities against both SARS-CoV and SARS-CoV-2 begin at 0.1 uM and infection is shut down 100% at 10 uM. It kills half the virus with just over 1 uM.
While the paper on chloroquine as a zinc ionophore didn't show that there is no zinc ionophore activity at 0.1-9.9 uM, the fact that it has only been shown at concentrations that are 100 times the minimum concentration required to kill all the virus and nine times the concentration required to kill half the virus makes it entirely unclear whether it has any effect at all at concentrations that are actually relevant.
The story gets worse, however.
When chloroquine brings zinc ions into the cell, they don't get distributed far and wide within the cell. Instead, they get stuck in a digestive organelle known as the lysosome.
Will lysosomal zinc kill SARS-CoV or SARS-CoV-2? Probably not.
Like many viruses, these ones enter the cell in little pockets of the cell membrane that invaginate, and then pinch off to form little bubbles. This process is called endocytosis (to bring within the cell), and the little bubble is called the endosome. Endosomes eventually fuse with lysosomes, where their contents will be digested and broken up into components that the cell needs. The viruses don't want to be digested and broken up. They will die. As a result, all viruses that enter through an endosome must escape the endosome before it fuses with a lysosome.
So, lysosomal zinc will not kill a virus. Viruses as a rule evade lysosomes.
Now, perhaps when chloroquine brings zinc into a cell, before it winds up in a lysosome it first travels through an endosome. And perhaps this endosomal zinc will kill the virus.
So, let's ask the question: how do SARS-CoV and SARS-CoV-2 escape the endosome, and could zinc kill them within the endosome or prevent them from escaping?
Zinc probably isn't directly toxic to these viruses. We know, for example, that coronavirus 229E survives fine on surfaces rich in zinc, but dies quickly on surfaces rich in copper. The copper kills this virus as well as SARS-CoV by generating oxidative stress, something zinc is very unlikely to do. While zinc inhibits a number of enzymes used by the virus, it's apparent lack of direct toxicity to the virus suggests that zinc isn't going to kill the virus just by being present in the endosome with it.
Might it prevent the virus from escaping the endosome?
At the time of writing, there are no published studies on how SARS-CoV-2 escapes the endosome, but SARS-CoV does so through the activity of the human enzyme cathepsin L. Although this enzyme can be inhibited by zinc in liver cells, the IC50 (the concentration required to inhibit the enzyme's activity by 50%) is around 50 micrograms per milliliter (ug/mL), which is 50 times the zinc concentration of plasma, and 50 times the zinc concentration that is probably present within an endosome when it first pinches off from a cell membrane. At 10 uM, which is the concentration at which chloroquine is 100% effective at stopping SARS-CoV infection, it roughly doubles the lysosomal zinc. But a doubling of the plasma concentration would push it to 2 ug/mL, which is still 25-fold lower than the IC50 against cathepsin L.
So, it seems very unlikely that endosomal zinc would prevent SARS-CoV or SARS-CoV-2 from escaping the endosome.
As I noted in The Food and Supplement Guide for the Coronavirus, there are two SARS-CoV enzymes known to be inhibited by zinc:
These proteins are not active in the endosome. Instead, SARS-CoV escapes the endosome and begins using the cellular machinery to read its RNA transcripts and produce proteins. This happens in the cytosol, the main compartment of the cell, or on the cytosolic surface of the endoplasmic reticulum, a cellular compartment dedicated to the production and processing of proteins. The SARS-CoV proteins that are inhibited by zinc are found embedded in the host cell's endoplasmic reticulum facing the cytosol.
The best chance for inhibiting viral replication, then, lies in increasing cytosolic zinc, not endosomal zinc.
But chloroquine doesn't increase cytosolic zinc. It traps zinc in lysosomes, where it is irrelevant to viral replication.
So how does chloroquine kill SARS-CoV and SARS-CoV-2 in vitro? Here's what those in vitro papers found:
As noted yesterday, despite the routine use of chloroquine against COVID-19 in China and its incorporation into at least two national guidelines for COVID-19, there is as yet no evidence it is effective.
In any case, what, if anything does this say about quercetin? I'll let you know tomorrow.
Stay safe,
Chris
A zinc ionophore is a compound that can bring zinc across a cellular membrane, thereby transporting the zinc into the cell, or into a specific location within the cell.
Although chloroquine has been shown to act as a zinc ionophore, I doubt this contributes to its antiviral activity against SARS-CoV, the coronavirus that causes SARS, or SARS-CoV-2, the coronavirus that causes COVID-19.
There are three big reasons for this:
- The concentrations shown to affect zinc transport are far higher than those required to kill the viruses.
- The zinc ionophore activity of chloroquine brings zinc into locations within the cell that would not be expected to kill the virus.
- Other effects that do occur at relevant concentrations have better support.
By contrast, chloroquine's antiviral activities against both SARS-CoV and SARS-CoV-2 begin at 0.1 uM and infection is shut down 100% at 10 uM. It kills half the virus with just over 1 uM.
While the paper on chloroquine as a zinc ionophore didn't show that there is no zinc ionophore activity at 0.1-9.9 uM, the fact that it has only been shown at concentrations that are 100 times the minimum concentration required to kill all the virus and nine times the concentration required to kill half the virus makes it entirely unclear whether it has any effect at all at concentrations that are actually relevant.
The story gets worse, however.
When chloroquine brings zinc ions into the cell, they don't get distributed far and wide within the cell. Instead, they get stuck in a digestive organelle known as the lysosome.
Will lysosomal zinc kill SARS-CoV or SARS-CoV-2? Probably not.
Like many viruses, these ones enter the cell in little pockets of the cell membrane that invaginate, and then pinch off to form little bubbles. This process is called endocytosis (to bring within the cell), and the little bubble is called the endosome. Endosomes eventually fuse with lysosomes, where their contents will be digested and broken up into components that the cell needs. The viruses don't want to be digested and broken up. They will die. As a result, all viruses that enter through an endosome must escape the endosome before it fuses with a lysosome.
So, lysosomal zinc will not kill a virus. Viruses as a rule evade lysosomes.
Now, perhaps when chloroquine brings zinc into a cell, before it winds up in a lysosome it first travels through an endosome. And perhaps this endosomal zinc will kill the virus.
So, let's ask the question: how do SARS-CoV and SARS-CoV-2 escape the endosome, and could zinc kill them within the endosome or prevent them from escaping?
Zinc probably isn't directly toxic to these viruses. We know, for example, that coronavirus 229E survives fine on surfaces rich in zinc, but dies quickly on surfaces rich in copper. The copper kills this virus as well as SARS-CoV by generating oxidative stress, something zinc is very unlikely to do. While zinc inhibits a number of enzymes used by the virus, it's apparent lack of direct toxicity to the virus suggests that zinc isn't going to kill the virus just by being present in the endosome with it.
Might it prevent the virus from escaping the endosome?
At the time of writing, there are no published studies on how SARS-CoV-2 escapes the endosome, but SARS-CoV does so through the activity of the human enzyme cathepsin L. Although this enzyme can be inhibited by zinc in liver cells, the IC50 (the concentration required to inhibit the enzyme's activity by 50%) is around 50 micrograms per milliliter (ug/mL), which is 50 times the zinc concentration of plasma, and 50 times the zinc concentration that is probably present within an endosome when it first pinches off from a cell membrane. At 10 uM, which is the concentration at which chloroquine is 100% effective at stopping SARS-CoV infection, it roughly doubles the lysosomal zinc. But a doubling of the plasma concentration would push it to 2 ug/mL, which is still 25-fold lower than the IC50 against cathepsin L.
So, it seems very unlikely that endosomal zinc would prevent SARS-CoV or SARS-CoV-2 from escaping the endosome.
As I noted in The Food and Supplement Guide for the Coronavirus, there are two SARS-CoV enzymes known to be inhibited by zinc:
- Papain-like protease 2 (PLP2) at an IC50 of 1.3 uM.
- 3CL protease at a Ki of 1.1 uM. (Ki and IC50 are both measures of half-maximal inhibition; you can read about the difference here).
These proteins are not active in the endosome. Instead, SARS-CoV escapes the endosome and begins using the cellular machinery to read its RNA transcripts and produce proteins. This happens in the cytosol, the main compartment of the cell, or on the cytosolic surface of the endoplasmic reticulum, a cellular compartment dedicated to the production and processing of proteins. The SARS-CoV proteins that are inhibited by zinc are found embedded in the host cell's endoplasmic reticulum facing the cytosol.
The best chance for inhibiting viral replication, then, lies in increasing cytosolic zinc, not endosomal zinc.
But chloroquine doesn't increase cytosolic zinc. It traps zinc in lysosomes, where it is irrelevant to viral replication.
So how does chloroquine kill SARS-CoV and SARS-CoV-2 in vitro? Here's what those in vitro papers found:
- It increases endosomal pH. Fusion of the virus with the endosome, and later escape of the virus from the endosome, can both be pH-dependent. Increasing endosomal pH appears to prevent fusion of SARS-CoV with the endosome, and to the extent it makes it in, might also prevent its escape into the cytosol. This is supported by the fact that ammonium chloride, another agent that increases endosomal pH, has the same effect.
- Chloroquine and ammonium chloride also raise the pH in the golgi apparatus, the compartment where sugars are added to proteins in a process known as glycosylation. ACE2, the protein on the cell surface that allows the entry of SARS-CoV and SARS-CoV-2 into the cell, is one of the proteins that are glycosylated in the golgi. Chloroquine and ammonium chloride both interrupt the glycosylation of ACE2. They do not affect the amount of ACE2 on the cell surface, but it is possible that the the virus is less able to dock to ACE2 when the protein hasn't been glycosylated.
As noted yesterday, despite the routine use of chloroquine against COVID-19 in China and its incorporation into at least two national guidelines for COVID-19, there is as yet no evidence it is effective.
In any case, what, if anything does this say about quercetin? I'll let you know tomorrow.
Stay safe,
Chris
As I explained in the last two updates (here and here) I've been studying hydroxychloroquine and chloroquine largely because I'm investigating whether their mechanisms shed any light on whether quercetin (rich in onions, nuts, and a variety of vegetables) and EGCG (abundant in green tea), are antiviral toward SARS-CoV-2 (the coronavirus that causes COVID-19) by acting as zinc ionophores. If they are, I might add them to the protocol in The Food and Supplement Guide for the Coronavirus.
In those two updates, we discussed how there remains no evidence that hydroxychloroquine or chloroquine are effective against COVID-19 in humans, and that their in vitro (in a lab dish) antiviral activity toward SARS-CoV-2 is likely a result of increasing the pH of endosomes and possibly a result of increasing the pH of the golgi apparatus, not by acting as zinc ionophores.
The endosome is a little bubble the virus uses to get into cells, and raising its pH (making it more alkaline and less acidic) prevents the virus from using it to get into the cell. The golgi apparatus is where the cell adds sugars to proteins in a process known as glycosylation, and raising the pH of the golgi interferes with that process. These drugs interfere with the glycosylation of ACE2, the protein the virus uses to attach to a cell. Although this hasn't been shown yet, decreased glycosylation of ACE2 might make it harder for the virus to attach to the cell.
A zinc ionophore is something that can bring zinc across a membrane into a cell or a specific compartment within the cell. Chloroquine has only been shown to do this at concentrations far higher than those needed to kill SARS-CoV-2 in vitro, and when it does so it traps the zinc in digestive compartments known as lysosomes, where the zinc would not be expected to kill the virus.
Quercetin and EGCG as Zinc Ionophores
Quercetin and EGCG have been also been shown to act as zinc ionophores.
However, I am even more doubtful that this is relevant to COVID-19 than I am for chloroquine. Here's why:
The study used 100 micromoles per liter (a measure of how many molecules there are per liter, abbreviated uM) of quercetin, EGCG, or an antitumor drug known to act as a zinc ionophore, clioquinol.
Supplementation with 1095 milligrams of quercetin only raises plasma concentrations to a little over 1 uM, which is 100 times lower than the concentrations used in this study. Supplementation with 500 milligrams of EGCG only raises plasma concentrations to 1.75 uM, which is 57 times lower than the concentrations used in this study.
Unrealistic Concentrations of Zinc
The study found no effect of quercetin or EGCG at 5 uM zinc. These compounds only enhanced zinc transport at 50 uM zinc.
Normal plasma concentrations of zinc range from 12 to 18 uM. Even in the hours just following a high-dose zinc supplement of 45 milligrams, plasma zinc does not go any higher than this range. Plasma zinc will never reach 50 uM with zinc supplements.
Furthermore, the zinc in this study was supplied as zinc chloride, which will be present in the freely available ionic form. By contrast, in plasma, 75-90% of zinc is bound to a protein known as albumin, and most of the rest is bound to α2-macroglobulin, a protein that prevents blood clotting, or retinol-binding protein, a protein that carries vitamin A. Freely available ionic zinc is only about 80 nanomoles per liter. A nanomole is one thousandth of a micromole, so the freely available zinc concentration used in the study was 60 times the concentration in plasma when EGCG and quercetin had no effect and 603 times the concentration in plasma when EGCG and quercetin did have an effect.
Now, it's not 100% clear to me that we should disregard the protein-bound zinc within plasma. It's conceivable that EGCG and quercetin could siphon zinc off from albumin to bring into the cell. However, even assuming all of the protein-bound zinc in plasma is just as available as the zinc chloride used in the study, the study still needed to use 3.3 times the total zinc found in plasma.
So far to show a zinc ionophore effect of these molecules we need two things:
Now we can borrow one key insight from our study of chloroquine. One of the reasons chloroquine probably doesn't kill SARS-CoV-2 in vitro by acting as a zinc ionophore is because chloroquine traps zinc in digestive compartments known as lysosomes, where the zinc would have no effect on the virus. In order to stop the replication of the virus, we want the zinc to be in the cytosol, the main compartment of the cell.
Do EGCG and quercetin increase cytosolic zinc (good) or lysosomal zinc (useless)?
We really have no idea.
The method used to detect zinc in this study was called FluoZin-3. When it encounters "labile zinc," a small minority of intracellular zinc that is either free ionic zinc or loosely bound zinc, FluoZin-3 fluoresces. Unfortunately, FluoZin-3 is not able to distinguish between cytosolic zinc and lysosomal zinc.
Whether the zinc is cytosolic (good) or lysosomal (useless) is probably irrelevant because the effect requires 50-100 times the reachable concentrations of quercetin or EGCG and either 3 times the normal concentration of total zinc or possibly more than 600 times the normal concentration of free zinc.
Quercetin as a Potential Inhibitor of the Viral 3CL Protease
A more promising paper used computer modeling software to predict that quercetin and EGCG inhibit one of the enzymes that SARS-CoV-2 uses to replicate, known as 3CL protease. The model predicts that EGCG would inhibit 50% of the enzyme's activity at a concentration of 13 uM, which is still seven times what can be reached in plasma with supplements. By contrast, it predicts that quercetin inhibits the enzyme at 0.7 uM, well within the concentrations that can be reached in plasma using 1000 milligram doses.
This might make quercetin, but not EGCG, useful for COVID-19 prevention or early treatment, but it should be regarded as very preliminary.
As noted yesterday, the SARS-CoV-2 3CL protease is found embedded in the membrane of the endoplasmic reticulum, with its enzymatic activity facing the cytosol. When cells are incubated with quercetin, much of it winds up embedded in the membrane of the endoplasmic reticulum as well. If we take the computer model's prediction at face value, it still isn't clear whether the quercetin embedded in the membrane would have the opportunity to inhibit the viral enzyme, given that the active part of the enzyme is facing the cytosol rather than the interior of the membrane. Still, it does make it's way to the correct location.
Whether quercetin inhibits the enzyme at all, however, still isn't known. Computer modeling is only a way of brainstorming possible interactions between molecules that can later be tested directly. The pharmaceutical industry uses the technique to come up with lists of drug candidates that can then be selected to undergo further testing to determine whether they actually have the activities the computer model predicted. To learn more about the limitations of this modeling and why its predictions can be wrong, see here, and skip to the fourth instance of "limitations" when keyword searching the page.
The Verdict
At the moment, I am exceedingly doubtful that quercetin or EGCG can kill SARS-CoV-2 by acting as zinc ionophores. I find the predicted inhibition of the 3CL protease by realistic concentrations of quercetin to be promising, but I would like to see at a minimum a paper showing that quercetin has this effect in cells infected with the virus before I would consider adding it to my prevention regimen.
I will continue to monitor the research, especially on the potential of quercetin to inhibit viral replication enzymes, but at this time, I will not be updating The Food and Supplement Guide for the Coronavirus to include EGCG or quercetin.
Stay safe,
Chris
In those two updates, we discussed how there remains no evidence that hydroxychloroquine or chloroquine are effective against COVID-19 in humans, and that their in vitro (in a lab dish) antiviral activity toward SARS-CoV-2 is likely a result of increasing the pH of endosomes and possibly a result of increasing the pH of the golgi apparatus, not by acting as zinc ionophores.
The endosome is a little bubble the virus uses to get into cells, and raising its pH (making it more alkaline and less acidic) prevents the virus from using it to get into the cell. The golgi apparatus is where the cell adds sugars to proteins in a process known as glycosylation, and raising the pH of the golgi interferes with that process. These drugs interfere with the glycosylation of ACE2, the protein the virus uses to attach to a cell. Although this hasn't been shown yet, decreased glycosylation of ACE2 might make it harder for the virus to attach to the cell.
A zinc ionophore is something that can bring zinc across a membrane into a cell or a specific compartment within the cell. Chloroquine has only been shown to do this at concentrations far higher than those needed to kill SARS-CoV-2 in vitro, and when it does so it traps the zinc in digestive compartments known as lysosomes, where the zinc would not be expected to kill the virus.
Quercetin and EGCG as Zinc Ionophores
Quercetin and EGCG have been also been shown to act as zinc ionophores.
However, I am even more doubtful that this is relevant to COVID-19 than I am for chloroquine. Here's why:
- The concentrations used are far higher than those even reachable with supplements; at least the concentrations of chloroquine that kill SARS-CoV-2 and begin to act as a zinc ionophore are reachable by taking the drug.
- In order for the effect to occur, zinc concentrations also have to be far higher than they ever are in humans.
- It is not clear whether the zinc would be in a relevant location within the cell.
The study used 100 micromoles per liter (a measure of how many molecules there are per liter, abbreviated uM) of quercetin, EGCG, or an antitumor drug known to act as a zinc ionophore, clioquinol.
Supplementation with 1095 milligrams of quercetin only raises plasma concentrations to a little over 1 uM, which is 100 times lower than the concentrations used in this study. Supplementation with 500 milligrams of EGCG only raises plasma concentrations to 1.75 uM, which is 57 times lower than the concentrations used in this study.
Unrealistic Concentrations of Zinc
The study found no effect of quercetin or EGCG at 5 uM zinc. These compounds only enhanced zinc transport at 50 uM zinc.
Normal plasma concentrations of zinc range from 12 to 18 uM. Even in the hours just following a high-dose zinc supplement of 45 milligrams, plasma zinc does not go any higher than this range. Plasma zinc will never reach 50 uM with zinc supplements.
Furthermore, the zinc in this study was supplied as zinc chloride, which will be present in the freely available ionic form. By contrast, in plasma, 75-90% of zinc is bound to a protein known as albumin, and most of the rest is bound to α2-macroglobulin, a protein that prevents blood clotting, or retinol-binding protein, a protein that carries vitamin A. Freely available ionic zinc is only about 80 nanomoles per liter. A nanomole is one thousandth of a micromole, so the freely available zinc concentration used in the study was 60 times the concentration in plasma when EGCG and quercetin had no effect and 603 times the concentration in plasma when EGCG and quercetin did have an effect.
Now, it's not 100% clear to me that we should disregard the protein-bound zinc within plasma. It's conceivable that EGCG and quercetin could siphon zinc off from albumin to bring into the cell. However, even assuming all of the protein-bound zinc in plasma is just as available as the zinc chloride used in the study, the study still needed to use 3.3 times the total zinc found in plasma.
So far to show a zinc ionophore effect of these molecules we need two things:
- 57 times as much EGCG or 100 times as much quercetin as achievable with oral supplements.
- At least >3 times the total zinc found in plasma, and possibly >600 times the ionic zinc found in plasma.
Now we can borrow one key insight from our study of chloroquine. One of the reasons chloroquine probably doesn't kill SARS-CoV-2 in vitro by acting as a zinc ionophore is because chloroquine traps zinc in digestive compartments known as lysosomes, where the zinc would have no effect on the virus. In order to stop the replication of the virus, we want the zinc to be in the cytosol, the main compartment of the cell.
Do EGCG and quercetin increase cytosolic zinc (good) or lysosomal zinc (useless)?
We really have no idea.
The method used to detect zinc in this study was called FluoZin-3. When it encounters "labile zinc," a small minority of intracellular zinc that is either free ionic zinc or loosely bound zinc, FluoZin-3 fluoresces. Unfortunately, FluoZin-3 is not able to distinguish between cytosolic zinc and lysosomal zinc.
Whether the zinc is cytosolic (good) or lysosomal (useless) is probably irrelevant because the effect requires 50-100 times the reachable concentrations of quercetin or EGCG and either 3 times the normal concentration of total zinc or possibly more than 600 times the normal concentration of free zinc.
Quercetin as a Potential Inhibitor of the Viral 3CL Protease
A more promising paper used computer modeling software to predict that quercetin and EGCG inhibit one of the enzymes that SARS-CoV-2 uses to replicate, known as 3CL protease. The model predicts that EGCG would inhibit 50% of the enzyme's activity at a concentration of 13 uM, which is still seven times what can be reached in plasma with supplements. By contrast, it predicts that quercetin inhibits the enzyme at 0.7 uM, well within the concentrations that can be reached in plasma using 1000 milligram doses.
This might make quercetin, but not EGCG, useful for COVID-19 prevention or early treatment, but it should be regarded as very preliminary.
As noted yesterday, the SARS-CoV-2 3CL protease is found embedded in the membrane of the endoplasmic reticulum, with its enzymatic activity facing the cytosol. When cells are incubated with quercetin, much of it winds up embedded in the membrane of the endoplasmic reticulum as well. If we take the computer model's prediction at face value, it still isn't clear whether the quercetin embedded in the membrane would have the opportunity to inhibit the viral enzyme, given that the active part of the enzyme is facing the cytosol rather than the interior of the membrane. Still, it does make it's way to the correct location.
Whether quercetin inhibits the enzyme at all, however, still isn't known. Computer modeling is only a way of brainstorming possible interactions between molecules that can later be tested directly. The pharmaceutical industry uses the technique to come up with lists of drug candidates that can then be selected to undergo further testing to determine whether they actually have the activities the computer model predicted. To learn more about the limitations of this modeling and why its predictions can be wrong, see here, and skip to the fourth instance of "limitations" when keyword searching the page.
The Verdict
At the moment, I am exceedingly doubtful that quercetin or EGCG can kill SARS-CoV-2 by acting as zinc ionophores. I find the predicted inhibition of the 3CL protease by realistic concentrations of quercetin to be promising, but I would like to see at a minimum a paper showing that quercetin has this effect in cells infected with the virus before I would consider adding it to my prevention regimen.
I will continue to monitor the research, especially on the potential of quercetin to inhibit viral replication enzymes, but at this time, I will not be updating The Food and Supplement Guide for the Coronavirus to include EGCG or quercetin.
Stay safe,
Chris
And now for today's newsletter:
New research suggests SARS-CoV-2 infects the throat, which makes important differences in how I will approach prevention.
Why This Matters
When I first wrote The Food and Supplement Guide for the Coronavirus, I took the position that SARS-CoV-2, the coronavirus that causes COVID-19, was most likely mainly infecting the lung without infecting parts of the upper respiratory tract such as the nose, mouth, or throat. However, I considered it open to further research and certain aspects of the protocol were meant as a hedge against the possibility that infection might begin in the upper respiratory tract.
For example, I focus on getting lots of oral zinc to raise systemic zinc status and get zinc into high concentrations of the lung. As a hedge against the possibility that the virus infects the nose, mouth, or throat, I put a small emphasis on getting some zinc in the form of zinc acetate lozenges, which are designed to disperse ionic zinc into those tissues.
As another example, I focus overwhelmingly on getting enough copper in the diet, mainly as food, to balance the zinc. As a hedge against the possibility that the virus infects the nose, mouth, or throat, I suggest the optional addition of a small amount of copper supplied in the form of a couple sprays of ionic copper into the mouth and throat.
Why Infection of the Nose, Mouth, and Throat Initially Seemed Unlikely
One of the reasons I found it unlikely the virus would infect the upper respiratory tract has to do with the location of ACE2, the protein on the cell surface that the virus uses to get into our cells.
A 2004 paper, published when SARS was the major concern (whose virus also uses ACE2 to get into the cell), used immunohistochemistry to determine the expression of the ACE2 protein in human tissues. This is a technique that uses a specific antibody to the ACE2 protein that can then be stained and visualized under a microscope. They found high expression on the surface of the lungs. Although they found ACE2 expressed in the oral and nasal mucosa, they found it all located on the basolateral side of the cell rather than the apical side of the cell. That's a fancy way of saying that the ACE2 is underneath the surface layer and faces away from the environment, so it wouldn't be available for an incoming virus to latch on to it.
On the other hand, a very recent paper in Nature showed that ACE2 is highly expressed in the oral cavity, with the highest expression on the tongue. But they found this by measuring RNA. Although that suggests the cells were making the ACE2 protein, it doesn't tell us whether it was on the environment-facing side of the cell or tucked underneath it.
Furthermore, early reports were suggesting that upper respiratory symptoms were rare. The common presence of a dry cough and rare addition of a runny nose or sore throat seemed consistent with a virus that infects the lungs but stays mostly clear of the nose, mouth, and throat.
Why the Case Remained Open
Still, without direct evidence measuring the live virus or signs of its replication in specific tissues, I considered the case open. Furthermore, in a recent discussion with Avi Bitton, MD, Avi pointed out to me that virions (virus particles) are small enough that they might be able to slip in between cells and access ACE2 underneath the environment-facing surface layer. This would allow them to get inside the cells of the nose, mouth, and throat, where they could hijack the cell's protein-producing machinery to start replicating.
New Information Shows the Virus Does Infect the Throat
A more recent German study, published as a preprint and not-yet peer reviewed, provides very direct evidence that SARS-CoV-2 infects and replicates in the throat.
Many cases of COVID-19 are identified based on symptoms first, and then testing to confirm. Since the testing is only done when the symptoms seem like a compelling case of COVID-19, the testing is biased toward the prevailing beliefs about the tell-tale symptoms. This makes the bias confirm itself: doctors only test when the symptoms cluster according to the early beliefs; therefore, cases where the symptoms differ from those beliefs are never tested and never confirmed.
For this paper, they identified people by testing individuals who had been in close association with already diagnosed cases, rather than individuals who had been identified by their symptoms. This allowed them to avoid that bias.
The patients were nine young to middle-aged professionals without underlying disease, and they all had mild self-resolving cases.
They tested for the viral RNA (which contains the virus's genetic information and suggests the presence of the virus) using either swabs of the nose and throat, or swabs of the mouth and throat. They also tested for viral RNA in sputum (phlegm), which mainly reflects what is coughed up from the lungs, and in stool.
They found no difference between the amount of viral RNA in nose-and-throat vs. mouth-and-throat swabs. In two cases, viral loads were higher in swabs than sputum; in two cases viral loads in sputum were higher than swab; in five they were similar.
The presence of viral RNA in a tissue does not show with any certainty that the virus is infecting the cells of that tissue. It is entirely possible that the virus is infecting the lung, and yet viruses are “shedding” and moving their way up the respiratory tract into the throat.
To rule that out, the researchers measured viral subgenomic messenger RNAs (sgRNAs), which are only transcribed in infected host cells and not packaged into virions. The presence of sgRNAs in a tissue provides very compelling evidence that the virus is infecting the cells of that tissue.
In throat swabs, sgRNAs were present for the first five days after symptoms started, but then disappeared. They persisted in sputum, by contrast, through at least day 9 of symptoms.
This suggests that the throat is infected early in the disease but clears relatively quickly, while infection in the lungs is stronger and persists for longer.
They were also able to isolate live viruses, usually from sputum, but often from the throat swabs.
In one patient, the viral genome in her throat swab developed a mutation. On the first day the mutation was detected, the viral genome in her sputum still contained the original gene. This strongly supported the interpretation that the virus was independently replicating in her throat.
It seems likely to me now that the infection starts in the nose, mouth, and throat. This is where the virus first enters, and where the virus must pass through to get to the lungs.
This study found that viral loads were already declining in throat swabs when symptoms started. In some of the patients, viral loads were also declining in sputum, but they declined more slowly and lasted longer. In a few patients, viral loads were increasing in sputum after symptoms started. The two patients whose viral loads peaked in sputum in the second week of symptoms were the same two patients who developed some initial signs of pneumonia.
All in all, it seems like the infection starts in the nose, mouth, or throat, and travels into the lung. In the lung, it is stronger and lasts longer. The stronger it gets in the lung and the longer it lasts there, the more likely someone is to have the severe symptoms associated with the pneumonia.
Key Differences From SARS
SARS-CoV, which caused the SARS outbreak of 2003, has a set of proteins that are on average 87% identical to SARS-CoV-2, which causes COVID-19. It therefore makes sense to compare and contrast the two.
In SARS, upper respiratory symptoms were rare, throat swabs were most often negative, and the live virus could never be isolated from throat swabs. That's quite different from COVID-19, where throat swabs are good at identifying cases and the live virus can be isolated from throat swabs many times.
COVID-19 seems to differ from SARS in that the virus replicates more quickly and initially does so in the upper respiratory tract. This allows it to achieve high viral loads in the upper respiratory tract that are easily spread from one person to another. As a result, it spreads much more easily than SARS. Later on in the infection, the viral load peaks in the lungs and COVID-19 begins to resemble SARS in its potential to cause serious damage to the lungs.
Why this difference? The authors suggest that it is because of a difference in the spike protein of the two viruses. The spike protein is the protein the virus uses to bind to ACE2 and enter into the cell. While both viruses bind to ACE2, SARS-CoV-2 cleaves its spike protein into two parts, and SARS-CoV does not. This appears to give SARS-CoV-2 better ability to bind to ACE2 and fuse with the cell membrane. They suggest that in tissues where ACE2 is expressed in a lower amount (or, I would add, perhaps where the ACE2 is harder to reach because of its location in the cell surface), SARS-CoV-2 has a better ability to infect than SARS-CoV. In this case, that means that SARS-CoV-2 can infect tissues of the nose, mouth, and throat much more effectively than SARS-CoV.
Still, the fact that this is mostly a lung disease and the most serious consequences are all in the lungs reflects the fact that the higher ACE2 expression in the lung drives a much more significant infection rate in that tissue. ACE2 still winds up being a key determinant of what tissue gets infected, and individual differences in its expression are almost certainly key determinants of differing susceptibility to disease.
A Quick Note on the Gut
The other tissue where ACE2 is highly expressed besides the lung is the gut. This is why both SARS and COVID-19 can cause diarrhea.
Still, the diarrhea is an uncommon feature.
In this study, viral RNA was found in high amounts in stool, and it tended to correlate with the amount of viral RNA in sputum. However, they were never able to isolate live virus or sgRNA from the stool. They suggested that something about the gut environment might neutralize the virus and render it incapable of infection.
What This Changes
As a result of this research, I will soon be updating The Food and Supplement Guide for the Coronavirus to put a greater emphasis on increasing zinc and copper concentrations in the mouth and throat through lozenges and sprays, I'll be considering copper-based nasal sprays, and I'll be researching whether it makes sense to use certain herbal or food components in the form of lozenges.
While these email updates are a free service and I do not want you to feel any pressure to purchase the guide if you haven't already, please know that updates are free, and if you choose to purchase it now, you will automatically get emailed the updates as soon as I make them.
Stay safe,
Chris
New research suggests SARS-CoV-2 infects the throat, which makes important differences in how I will approach prevention.
Why This Matters
When I first wrote The Food and Supplement Guide for the Coronavirus, I took the position that SARS-CoV-2, the coronavirus that causes COVID-19, was most likely mainly infecting the lung without infecting parts of the upper respiratory tract such as the nose, mouth, or throat. However, I considered it open to further research and certain aspects of the protocol were meant as a hedge against the possibility that infection might begin in the upper respiratory tract.
For example, I focus on getting lots of oral zinc to raise systemic zinc status and get zinc into high concentrations of the lung. As a hedge against the possibility that the virus infects the nose, mouth, or throat, I put a small emphasis on getting some zinc in the form of zinc acetate lozenges, which are designed to disperse ionic zinc into those tissues.
As another example, I focus overwhelmingly on getting enough copper in the diet, mainly as food, to balance the zinc. As a hedge against the possibility that the virus infects the nose, mouth, or throat, I suggest the optional addition of a small amount of copper supplied in the form of a couple sprays of ionic copper into the mouth and throat.
Why Infection of the Nose, Mouth, and Throat Initially Seemed Unlikely
One of the reasons I found it unlikely the virus would infect the upper respiratory tract has to do with the location of ACE2, the protein on the cell surface that the virus uses to get into our cells.
A 2004 paper, published when SARS was the major concern (whose virus also uses ACE2 to get into the cell), used immunohistochemistry to determine the expression of the ACE2 protein in human tissues. This is a technique that uses a specific antibody to the ACE2 protein that can then be stained and visualized under a microscope. They found high expression on the surface of the lungs. Although they found ACE2 expressed in the oral and nasal mucosa, they found it all located on the basolateral side of the cell rather than the apical side of the cell. That's a fancy way of saying that the ACE2 is underneath the surface layer and faces away from the environment, so it wouldn't be available for an incoming virus to latch on to it.
On the other hand, a very recent paper in Nature showed that ACE2 is highly expressed in the oral cavity, with the highest expression on the tongue. But they found this by measuring RNA. Although that suggests the cells were making the ACE2 protein, it doesn't tell us whether it was on the environment-facing side of the cell or tucked underneath it.
Furthermore, early reports were suggesting that upper respiratory symptoms were rare. The common presence of a dry cough and rare addition of a runny nose or sore throat seemed consistent with a virus that infects the lungs but stays mostly clear of the nose, mouth, and throat.
Why the Case Remained Open
Still, without direct evidence measuring the live virus or signs of its replication in specific tissues, I considered the case open. Furthermore, in a recent discussion with Avi Bitton, MD, Avi pointed out to me that virions (virus particles) are small enough that they might be able to slip in between cells and access ACE2 underneath the environment-facing surface layer. This would allow them to get inside the cells of the nose, mouth, and throat, where they could hijack the cell's protein-producing machinery to start replicating.
New Information Shows the Virus Does Infect the Throat
A more recent German study, published as a preprint and not-yet peer reviewed, provides very direct evidence that SARS-CoV-2 infects and replicates in the throat.
Many cases of COVID-19 are identified based on symptoms first, and then testing to confirm. Since the testing is only done when the symptoms seem like a compelling case of COVID-19, the testing is biased toward the prevailing beliefs about the tell-tale symptoms. This makes the bias confirm itself: doctors only test when the symptoms cluster according to the early beliefs; therefore, cases where the symptoms differ from those beliefs are never tested and never confirmed.
For this paper, they identified people by testing individuals who had been in close association with already diagnosed cases, rather than individuals who had been identified by their symptoms. This allowed them to avoid that bias.
The patients were nine young to middle-aged professionals without underlying disease, and they all had mild self-resolving cases.
They tested for the viral RNA (which contains the virus's genetic information and suggests the presence of the virus) using either swabs of the nose and throat, or swabs of the mouth and throat. They also tested for viral RNA in sputum (phlegm), which mainly reflects what is coughed up from the lungs, and in stool.
They found no difference between the amount of viral RNA in nose-and-throat vs. mouth-and-throat swabs. In two cases, viral loads were higher in swabs than sputum; in two cases viral loads in sputum were higher than swab; in five they were similar.
The presence of viral RNA in a tissue does not show with any certainty that the virus is infecting the cells of that tissue. It is entirely possible that the virus is infecting the lung, and yet viruses are “shedding” and moving their way up the respiratory tract into the throat.
To rule that out, the researchers measured viral subgenomic messenger RNAs (sgRNAs), which are only transcribed in infected host cells and not packaged into virions. The presence of sgRNAs in a tissue provides very compelling evidence that the virus is infecting the cells of that tissue.
In throat swabs, sgRNAs were present for the first five days after symptoms started, but then disappeared. They persisted in sputum, by contrast, through at least day 9 of symptoms.
This suggests that the throat is infected early in the disease but clears relatively quickly, while infection in the lungs is stronger and persists for longer.
They were also able to isolate live viruses, usually from sputum, but often from the throat swabs.
In one patient, the viral genome in her throat swab developed a mutation. On the first day the mutation was detected, the viral genome in her sputum still contained the original gene. This strongly supported the interpretation that the virus was independently replicating in her throat.
It seems likely to me now that the infection starts in the nose, mouth, and throat. This is where the virus first enters, and where the virus must pass through to get to the lungs.
This study found that viral loads were already declining in throat swabs when symptoms started. In some of the patients, viral loads were also declining in sputum, but they declined more slowly and lasted longer. In a few patients, viral loads were increasing in sputum after symptoms started. The two patients whose viral loads peaked in sputum in the second week of symptoms were the same two patients who developed some initial signs of pneumonia.
All in all, it seems like the infection starts in the nose, mouth, or throat, and travels into the lung. In the lung, it is stronger and lasts longer. The stronger it gets in the lung and the longer it lasts there, the more likely someone is to have the severe symptoms associated with the pneumonia.
Key Differences From SARS
SARS-CoV, which caused the SARS outbreak of 2003, has a set of proteins that are on average 87% identical to SARS-CoV-2, which causes COVID-19. It therefore makes sense to compare and contrast the two.
In SARS, upper respiratory symptoms were rare, throat swabs were most often negative, and the live virus could never be isolated from throat swabs. That's quite different from COVID-19, where throat swabs are good at identifying cases and the live virus can be isolated from throat swabs many times.
COVID-19 seems to differ from SARS in that the virus replicates more quickly and initially does so in the upper respiratory tract. This allows it to achieve high viral loads in the upper respiratory tract that are easily spread from one person to another. As a result, it spreads much more easily than SARS. Later on in the infection, the viral load peaks in the lungs and COVID-19 begins to resemble SARS in its potential to cause serious damage to the lungs.
Why this difference? The authors suggest that it is because of a difference in the spike protein of the two viruses. The spike protein is the protein the virus uses to bind to ACE2 and enter into the cell. While both viruses bind to ACE2, SARS-CoV-2 cleaves its spike protein into two parts, and SARS-CoV does not. This appears to give SARS-CoV-2 better ability to bind to ACE2 and fuse with the cell membrane. They suggest that in tissues where ACE2 is expressed in a lower amount (or, I would add, perhaps where the ACE2 is harder to reach because of its location in the cell surface), SARS-CoV-2 has a better ability to infect than SARS-CoV. In this case, that means that SARS-CoV-2 can infect tissues of the nose, mouth, and throat much more effectively than SARS-CoV.
Still, the fact that this is mostly a lung disease and the most serious consequences are all in the lungs reflects the fact that the higher ACE2 expression in the lung drives a much more significant infection rate in that tissue. ACE2 still winds up being a key determinant of what tissue gets infected, and individual differences in its expression are almost certainly key determinants of differing susceptibility to disease.
A Quick Note on the Gut
The other tissue where ACE2 is highly expressed besides the lung is the gut. This is why both SARS and COVID-19 can cause diarrhea.
Still, the diarrhea is an uncommon feature.
In this study, viral RNA was found in high amounts in stool, and it tended to correlate with the amount of viral RNA in sputum. However, they were never able to isolate live virus or sgRNA from the stool. They suggested that something about the gut environment might neutralize the virus and render it incapable of infection.
What This Changes
As a result of this research, I will soon be updating The Food and Supplement Guide for the Coronavirus to put a greater emphasis on increasing zinc and copper concentrations in the mouth and throat through lozenges and sprays, I'll be considering copper-based nasal sprays, and I'll be researching whether it makes sense to use certain herbal or food components in the form of lozenges.
While these email updates are a free service and I do not want you to feel any pressure to purchase the guide if you haven't already, please know that updates are free, and if you choose to purchase it now, you will automatically get emailed the updates as soon as I make them.
Stay safe,
Chris
A new study (as with virtually all circulating information on COVID-19, not yet peer-reviewed), shows that ACE2 can easily explain why smoking is correlated with worse outcomes in COVID-19.
Background
ACE2 is an enzyme whose normal role in our physiology is to lower our blood pressure, and to prevent damage to tissues from fibrosis (laying down of scar tissue) and excess proliferation (cells reproducing at too high a rate, as occurs in tumors, for example).
SARS-CoV-2, the coronavirus that causes COVID-19, hijacks ACE2 on the cell surface in order to gain entry into the cell. All viruses must enter the cells of their host in order to hijack their protein-producing machinery, which they must do in order to replicate. No cell entry, no infection.
Since ACE2 is the entryway for SARS-CoV-2, it is the overwhelming determinant of infection, after exposure. As discussed in the new paper, this is supported by several lines of evidence:
This is true despite the fact that ACE2 is protective of lung tissue, and that SARS causes damage by binding up the ACE2 and preventing it from doing its job. Even though the loss of ACE2 plays a role in disease, it is the expression of ACE2 that allows the viral progression to become severe in the first place.
Smoking is a Risk Factor for Severe COVID-19 Outcomes
In COVID-19, one of the risk factors for disease severity is cigarette smoking. In a a cohort of 1099 cases of COVID-19, only 4.7% of non-smokers had progression to severe disease, such as ICU, ventilation, or death. In smokers, this rate was 12.3%.
In the current paper, the researchers found cigarette smoking to be a major determinant of ACE2 expression in the lung.
Smokings Have More ACE2 in Their Lungs
In three different cohorts, ACE2 expression was 50-60% higher in current smokers than non-smokers. Former smokers had similar levels of ACE2 as non-smokers, suggesting that quitting smoking is a good way to decrease ACE2 expression in the lung.
How much people had smoked for how long was also a major determinant of ACE2. This can be measured in pack-years, where the number of packs are multiplied by the number of years smoking. For example, smoking 1 packs a day for 20 years is 20 pack years. A smoking history of >80 pack years led to double the ACE2 compared to a history of <20 pack years.
Smoking Increases ACE2 by Increasing the Proportion of Mucus Cells
Then they looked at specific cell types.
ACE2 is mainly expressed in goblet cells, which secrete mucus, and club cells, which engulf toxins and break them down. Within individual cells of those two subtypes, they looked at the expression of other enzymes. The cells that made the most ACE2 were the cells that also made the most enzymes involved in antioxidant defense and detoxification.
Then they looked at how those subtypes differed in smokers and non-smokers. In epithelial cells of the bronchus (epithelial cells form the surface lining of tissues), 47% of cells in smokers were goblets, while only 17% of cells in non-smokers were goblets. In other words, smoking increases the proportion of mucus-producing, ACE2-expressing goblet cells by 2.8-fold.
Isolated lung epithelial cells can be put at the interface between air and a liquid, and this will make them turn into mucus-producing and cilia-producing cells. (Cilia are little hairlike projections that help brush along mucus and debris.) This is called mucociliary differentiation. Mucociliary differentiation increased ACE2 3-fold.
Exposing the cells to smoke increased ACE2 by 42%.
Conclusions
Altogether this shows that smoking increases mucus-producing cells as a means of protecting the airway from the smoke. ACE2, which is a protective enzyme under ordinary circumstances, increases as a result. Since it is the entryway of SARS-CoV-2 into cells, the higher ACE2 allows a greater rate of viral entry and thus a higher viral load, and thus a worse disease course.
Granted, chronic smoking is also associated with emphysema, atherosclerosis, and decreased immune function, and these may also play roles in COVID-19 severity. However, the ACE2 story offers a very clean explanation for why smoking predisposes to poor outcomes with this specific virus.
This suggests that quitting smoking will be protective, and it adds to the evidence that controlling ACE2 levels should be a primary strategy in prevention and early treatment.
Stay safe,
Chris
Background
ACE2 is an enzyme whose normal role in our physiology is to lower our blood pressure, and to prevent damage to tissues from fibrosis (laying down of scar tissue) and excess proliferation (cells reproducing at too high a rate, as occurs in tumors, for example).
SARS-CoV-2, the coronavirus that causes COVID-19, hijacks ACE2 on the cell surface in order to gain entry into the cell. All viruses must enter the cells of their host in order to hijack their protein-producing machinery, which they must do in order to replicate. No cell entry, no infection.
Since ACE2 is the entryway for SARS-CoV-2, it is the overwhelming determinant of infection, after exposure. As discussed in the new paper, this is supported by several lines of evidence:
- Blocking ACE2 with specific antibodies prevents SARS-CoV from infecting a cell.
- Cells that do not express ACE2 cannot be infected. However, experimentally inserting ACE2 into these cells allows them to be infected.
This is true despite the fact that ACE2 is protective of lung tissue, and that SARS causes damage by binding up the ACE2 and preventing it from doing its job. Even though the loss of ACE2 plays a role in disease, it is the expression of ACE2 that allows the viral progression to become severe in the first place.
Smoking is a Risk Factor for Severe COVID-19 Outcomes
In COVID-19, one of the risk factors for disease severity is cigarette smoking. In a a cohort of 1099 cases of COVID-19, only 4.7% of non-smokers had progression to severe disease, such as ICU, ventilation, or death. In smokers, this rate was 12.3%.
In the current paper, the researchers found cigarette smoking to be a major determinant of ACE2 expression in the lung.
Smokings Have More ACE2 in Their Lungs
In three different cohorts, ACE2 expression was 50-60% higher in current smokers than non-smokers. Former smokers had similar levels of ACE2 as non-smokers, suggesting that quitting smoking is a good way to decrease ACE2 expression in the lung.
How much people had smoked for how long was also a major determinant of ACE2. This can be measured in pack-years, where the number of packs are multiplied by the number of years smoking. For example, smoking 1 packs a day for 20 years is 20 pack years. A smoking history of >80 pack years led to double the ACE2 compared to a history of <20 pack years.
Smoking Increases ACE2 by Increasing the Proportion of Mucus Cells
Then they looked at specific cell types.
ACE2 is mainly expressed in goblet cells, which secrete mucus, and club cells, which engulf toxins and break them down. Within individual cells of those two subtypes, they looked at the expression of other enzymes. The cells that made the most ACE2 were the cells that also made the most enzymes involved in antioxidant defense and detoxification.
Then they looked at how those subtypes differed in smokers and non-smokers. In epithelial cells of the bronchus (epithelial cells form the surface lining of tissues), 47% of cells in smokers were goblets, while only 17% of cells in non-smokers were goblets. In other words, smoking increases the proportion of mucus-producing, ACE2-expressing goblet cells by 2.8-fold.
Isolated lung epithelial cells can be put at the interface between air and a liquid, and this will make them turn into mucus-producing and cilia-producing cells. (Cilia are little hairlike projections that help brush along mucus and debris.) This is called mucociliary differentiation. Mucociliary differentiation increased ACE2 3-fold.
Exposing the cells to smoke increased ACE2 by 42%.
Conclusions
Altogether this shows that smoking increases mucus-producing cells as a means of protecting the airway from the smoke. ACE2, which is a protective enzyme under ordinary circumstances, increases as a result. Since it is the entryway of SARS-CoV-2 into cells, the higher ACE2 allows a greater rate of viral entry and thus a higher viral load, and thus a worse disease course.
Granted, chronic smoking is also associated with emphysema, atherosclerosis, and decreased immune function, and these may also play roles in COVID-19 severity. However, the ACE2 story offers a very clean explanation for why smoking predisposes to poor outcomes with this specific virus.
This suggests that quitting smoking will be protective, and it adds to the evidence that controlling ACE2 levels should be a primary strategy in prevention and early treatment.
Stay safe,
Chris
If you feel sick, what are the chances it's the coronavirus?
Researchers from the Los Angeles Departments of Public Health and Health Services and the Los Angeles County and University of Southern California Medical Center tested everyone who presented with mild flu-like illness to the emergency room or urgent care on March 12, 13, 15, and 16. They published their results yesterday in the Journal of the American Medical Association.
Their results are published as a research letter, so the publication is short and light on details. They don't describe how they categorized mild flu-like illness. However, the CDC lists flu symptoms as cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and fatigue. Some but not all people will have a fever, and occasionally the flu is accompanied by vomiting and diarrhea, though this is more common in children than adults.
In Los Angeles, the researchers ran 131 tests and found 7 positives for SARS-CoV-2, the coronavirus that causes COVID-19. That means the chances of having COVID-19 in this cohort when presenting with mild flu-like illness were 5.3%.
Six of the seven COVID-19 patients had a fever, five had muscle pain, and only one had a cough. All seven tested negative for the flu and for a related virus, the respiratory syncytial virus.
It is important to realize the proportions could be very different in other groups of people. For example the chances could be much higher if you live in New York City.
In fact, the proportion even in LA is probably much higher today than it was when the data was collected in mid-March. The day before the data collection, the entire state of California only had 177 cases. Today, the state has almost ten thousand, and Los Angeles County alone has 3,518.
The best lessons to learn from this are probably as follows:
Chris
Researchers from the Los Angeles Departments of Public Health and Health Services and the Los Angeles County and University of Southern California Medical Center tested everyone who presented with mild flu-like illness to the emergency room or urgent care on March 12, 13, 15, and 16. They published their results yesterday in the Journal of the American Medical Association.
Their results are published as a research letter, so the publication is short and light on details. They don't describe how they categorized mild flu-like illness. However, the CDC lists flu symptoms as cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and fatigue. Some but not all people will have a fever, and occasionally the flu is accompanied by vomiting and diarrhea, though this is more common in children than adults.
In Los Angeles, the researchers ran 131 tests and found 7 positives for SARS-CoV-2, the coronavirus that causes COVID-19. That means the chances of having COVID-19 in this cohort when presenting with mild flu-like illness were 5.3%.
Six of the seven COVID-19 patients had a fever, five had muscle pain, and only one had a cough. All seven tested negative for the flu and for a related virus, the respiratory syncytial virus.
It is important to realize the proportions could be very different in other groups of people. For example the chances could be much higher if you live in New York City.
In fact, the proportion even in LA is probably much higher today than it was when the data was collected in mid-March. The day before the data collection, the entire state of California only had 177 cases. Today, the state has almost ten thousand, and Los Angeles County alone has 3,518.
The best lessons to learn from this are probably as follows:
- If you live in an area where the reported cases are low, you probably have a 5% chance of having COVID-19 if you have a fever, muscle pain, or cough. You only need one of those to consider the chances 5%.
- If you live in an area where the reported cases are low, expect that to last for 2-3 weeks. Living in New York City, all I needed to do this entire time was know what my city would look like in 2-3 weeks by looking at Italy. Just look at the increase in LA County, and it's clearly lagging a little behind NYC. I wouldn't expect this to be different anywhere.
Chris
On Tuesday, I wrote to you about new study showing that SARS-CoV-2, the coronavirus that causes COVID-19, infects the throat, not just the lungs, and the infection may actually start in the throat before it starts in the lungs. And since the evidence for infecting the throat came from either oropharyngeal swabs (swabs of the mouth and throat) or from nasopharyngeal swabs (swabs of the nose and throat), it may well start in the nose or mouth as well as the throat. When I wrote to you, the paper was a preprint that had yet to be peer reviewed. Yesterday, just one day after I wrote to you, that paper was published in Nature.
Can we leverage this information toward preventing COVID-19?
Although there are no randomized controlled trials of any nutritional supplements in the prevention of COVID-19, I find it worthwhile to speculate. And when something is perfectly safe, and I think it might work, I'm going to take action on it. There's no way I can protect myself from being exposed to the virus 100%, so I will augment hygiene and social distancing with whatever seems to have the best chance of prevention.
Zinc inhibits two of the proteins involved in the replication of SARS-CoV (the 3CL protease and the papain-like protease 2), the coronavirus that causes SARS, and proteins between SARS-CoV and SARS-CoV-2 are on average 87% identical, so it's likely that zinc also inhibits these enzymes in SARS-CoV-2. In fact, these two proteins are known as “cysteine proteases” and their activity depends on the sulfur found in the amino acid cysteine. Zinc inhibits these proteins in SARS-CoV by binding to those sulfurs. Since those sulfurs are essential to the function of cysteine proteases across the board, then it's almost certain that zinc inhibits them in SARS-CoV-2 in exactly the same way.
There's no evidence that zinc is directly toxic to SARS-CoV or SARS-CoV-2. In fact, it probably is not, given that coronavirus 229E survives fine on zinc surfaces. So, zinc probably has little to no ability to kill the virus outside of cells, but enriching our own cells with zinc may well put a stop to the virus being able to replicate within them.
The best way to get zinc into the nose, mouth, and throat tissue is to use zinc acetate lozenges. They have been mainly studied in the context of the common cold (see here, here, and here), where they prevent rhinoviruses from docking to their cellular receptor, ICAM-1. Zinc acetate and zinc gluconate are both effective, but zinc acetate ionizes twice as effectively as zinc gluconate inside the mouth, and the ionization of the zinc allows it to migrate throughout the tissues of the mouth, nose, and throat.
Borrowing from the research on the common cold, I think the best way to enrich the tissues of the mouth, nose, and throat with zinc is to use zinc acetate lozenges at a low dose preventatively, at a more intensive dose when encountering a potential exposure to SARS-CoV-2, and at a dose used in common cold trials at the first sign of illness.
The only zinc lozenges on the market that fulfill all of the criteria to be effective against the common cold are Life Extension Enhanced Zinc Lozenges. They can be ordered now, though they say they are backordered until tomorrow (the site has said this for a month, so hopefully tomorrow they will be ready to ship).
For copper we have a different story. Copper has only been shown to inhibit SARS-CoV papain-like protease 2, but it requires almost ten times the concentration of zinc. Copper is probably a very poor inhibitor of viral replication. And yet, copper is extremely toxic to SARS-CoV and coronavirus 229E. This is shown by their inability to survive for longer than five to thirty minutes on copper surfaces, while they survive on most other surfaces for five to nine days. The copper causes oxidative stress, which these viruses have very poor defenses against. In fact, one of the hypotheses for why bats seem to tolerate thousands of coronaviruses without getting sick is that they have very rapid metabolisms and generate high levels of reactive oxygen species. Humans actually use copper to defend themselves from oxidative stress and can tolerate far more oxidative stress than microbes in general (this is why, for example, hydrogen peroxide has so much antimicrobial power, yet pouring some on a wound doesn't completely destroy our tissues).
Since copper surfaces are highly toxic to coronaviruses that have no host cells to actively replicate within, while copper probably isn't a strong inhibitor of viral replication, the main goal with copper for the mouth, nose, and throat should be to safely deliver high concentrations of copper directly to the surface of these tissues during times where we would expect the virus to have recently invaded.
In version 1.0 of the The Food and Supplement Guide for the Coronavirus, I considered it only a minor possibility that SARS-CoV-2 infects the mouth, nose, or throat. I recommended using a fine mist spray bottle to spray ionic copper into the mouth and throat as an optional add-on to the main protocol to get some of the daily copper in that would be needed to balance the high levels of oral zinc.
In a March 18 Twitter discussion, Avi Bitton, MD alerted my attention to the possibility that an ionic copper spray could irritate mucous membranes. In a March 25 verbal discussion published on YouTube, we discussed this further and agreed that copper delivered topically to these tissues would probably only be relevant when supplied very near in time to events of exposure to the virus. Neither of us had any idea what threshold of copper would definitely hurt mucous membranes or how long it might take to cause harm if someone didn't notice any major irritation, but we agreed that someone should pull back if they experience irritation and it should not be used indefinitely.
The best way to deliver topical copper salts to the nose, mouth, and throat without damaging the mucous membranes, in my current estimation, is by using Sterimar Stop and Protect Cold and Sinusitis Relief nasal spray. Sterimar is filtered, preservative-free seawater enriched in copper salts, with eucalyptus and hyaluronic acid. It is formulated to protect the mucous membranes of the nose, and it has been shown to be protective toward these mucous membranes in vitro.
Whereas the ionic copper spray I first recommended has an unpleasant metallic taste, the Sterimar spray pleasantly reminds me of the ocean. I find it can be comfortably sprayed into the nose as directed on the bottle, and can also be sprayed within the mouth.
On March 6, after reading about the toxic effect of copper toward SARS-CoV, I ordered a bottle of Sterimar Stop and Protect Cold and Sinusitis Relief nasal spray. At the time there were only four left, and I wasn't sure whether I would wind up using it yet, but I bought one just in case they sold out. This morning I tested their volume on Amazon and was able to add 500 to my cart. Instead, I ordered three bottles. However, I updated The Food and Supplement Guide for the Coronavirus a few hours ago and Amazon is now sold out. Nevertheless, if you Google the product, there are multiple other online sellers, and a quick sampling of mine shows that there are some available.
My current practice is to take one zinc acetate lozenge per day preventatively. Before and after any deliberate potential exposure event, such as going out in public, or after any accidental exposure event, such as an incorrect use of gloves or masks, forgetting to wash hands before eating, or sticking one's fingers into one's nose or mouth, I will take an extra zinc lozenge and use the Sterimar spray in both my nose and in my mouth and throat.
The Food and Supplement Guide for the Coronavirus has now been updated to version 2.0, reflecting my research through today, April 2, 2020. It contains these revisions of the protocol, as well as more detail on how to implement it. Right now I'm able to publish this newsletter on a daily basis because sales of the guide allow me to devote myself to full-time research on COVID-19. I am comprehensively reading all the titles of preprints and published papers on COVID-19, stopping to read abstracts or full papers where I find them likely to have practical relevance, as well as keyword searching intensively for specific topics I will comprehensively review on this list, such as ACE2 and the mechanisms of the cytokine storm. If you would like to purchase a copy of the guide, you will help make it possible for me to continue doing this research, and I will be very grateful for that.
Stay safe,
Chris
Can we leverage this information toward preventing COVID-19?
Although there are no randomized controlled trials of any nutritional supplements in the prevention of COVID-19, I find it worthwhile to speculate. And when something is perfectly safe, and I think it might work, I'm going to take action on it. There's no way I can protect myself from being exposed to the virus 100%, so I will augment hygiene and social distancing with whatever seems to have the best chance of prevention.
Zinc inhibits two of the proteins involved in the replication of SARS-CoV (the 3CL protease and the papain-like protease 2), the coronavirus that causes SARS, and proteins between SARS-CoV and SARS-CoV-2 are on average 87% identical, so it's likely that zinc also inhibits these enzymes in SARS-CoV-2. In fact, these two proteins are known as “cysteine proteases” and their activity depends on the sulfur found in the amino acid cysteine. Zinc inhibits these proteins in SARS-CoV by binding to those sulfurs. Since those sulfurs are essential to the function of cysteine proteases across the board, then it's almost certain that zinc inhibits them in SARS-CoV-2 in exactly the same way.
There's no evidence that zinc is directly toxic to SARS-CoV or SARS-CoV-2. In fact, it probably is not, given that coronavirus 229E survives fine on zinc surfaces. So, zinc probably has little to no ability to kill the virus outside of cells, but enriching our own cells with zinc may well put a stop to the virus being able to replicate within them.
The best way to get zinc into the nose, mouth, and throat tissue is to use zinc acetate lozenges. They have been mainly studied in the context of the common cold (see here, here, and here), where they prevent rhinoviruses from docking to their cellular receptor, ICAM-1. Zinc acetate and zinc gluconate are both effective, but zinc acetate ionizes twice as effectively as zinc gluconate inside the mouth, and the ionization of the zinc allows it to migrate throughout the tissues of the mouth, nose, and throat.
Borrowing from the research on the common cold, I think the best way to enrich the tissues of the mouth, nose, and throat with zinc is to use zinc acetate lozenges at a low dose preventatively, at a more intensive dose when encountering a potential exposure to SARS-CoV-2, and at a dose used in common cold trials at the first sign of illness.
The only zinc lozenges on the market that fulfill all of the criteria to be effective against the common cold are Life Extension Enhanced Zinc Lozenges. They can be ordered now, though they say they are backordered until tomorrow (the site has said this for a month, so hopefully tomorrow they will be ready to ship).
For copper we have a different story. Copper has only been shown to inhibit SARS-CoV papain-like protease 2, but it requires almost ten times the concentration of zinc. Copper is probably a very poor inhibitor of viral replication. And yet, copper is extremely toxic to SARS-CoV and coronavirus 229E. This is shown by their inability to survive for longer than five to thirty minutes on copper surfaces, while they survive on most other surfaces for five to nine days. The copper causes oxidative stress, which these viruses have very poor defenses against. In fact, one of the hypotheses for why bats seem to tolerate thousands of coronaviruses without getting sick is that they have very rapid metabolisms and generate high levels of reactive oxygen species. Humans actually use copper to defend themselves from oxidative stress and can tolerate far more oxidative stress than microbes in general (this is why, for example, hydrogen peroxide has so much antimicrobial power, yet pouring some on a wound doesn't completely destroy our tissues).
Since copper surfaces are highly toxic to coronaviruses that have no host cells to actively replicate within, while copper probably isn't a strong inhibitor of viral replication, the main goal with copper for the mouth, nose, and throat should be to safely deliver high concentrations of copper directly to the surface of these tissues during times where we would expect the virus to have recently invaded.
In version 1.0 of the The Food and Supplement Guide for the Coronavirus, I considered it only a minor possibility that SARS-CoV-2 infects the mouth, nose, or throat. I recommended using a fine mist spray bottle to spray ionic copper into the mouth and throat as an optional add-on to the main protocol to get some of the daily copper in that would be needed to balance the high levels of oral zinc.
In a March 18 Twitter discussion, Avi Bitton, MD alerted my attention to the possibility that an ionic copper spray could irritate mucous membranes. In a March 25 verbal discussion published on YouTube, we discussed this further and agreed that copper delivered topically to these tissues would probably only be relevant when supplied very near in time to events of exposure to the virus. Neither of us had any idea what threshold of copper would definitely hurt mucous membranes or how long it might take to cause harm if someone didn't notice any major irritation, but we agreed that someone should pull back if they experience irritation and it should not be used indefinitely.
The best way to deliver topical copper salts to the nose, mouth, and throat without damaging the mucous membranes, in my current estimation, is by using Sterimar Stop and Protect Cold and Sinusitis Relief nasal spray. Sterimar is filtered, preservative-free seawater enriched in copper salts, with eucalyptus and hyaluronic acid. It is formulated to protect the mucous membranes of the nose, and it has been shown to be protective toward these mucous membranes in vitro.
Whereas the ionic copper spray I first recommended has an unpleasant metallic taste, the Sterimar spray pleasantly reminds me of the ocean. I find it can be comfortably sprayed into the nose as directed on the bottle, and can also be sprayed within the mouth.
On March 6, after reading about the toxic effect of copper toward SARS-CoV, I ordered a bottle of Sterimar Stop and Protect Cold and Sinusitis Relief nasal spray. At the time there were only four left, and I wasn't sure whether I would wind up using it yet, but I bought one just in case they sold out. This morning I tested their volume on Amazon and was able to add 500 to my cart. Instead, I ordered three bottles. However, I updated The Food and Supplement Guide for the Coronavirus a few hours ago and Amazon is now sold out. Nevertheless, if you Google the product, there are multiple other online sellers, and a quick sampling of mine shows that there are some available.
My current practice is to take one zinc acetate lozenge per day preventatively. Before and after any deliberate potential exposure event, such as going out in public, or after any accidental exposure event, such as an incorrect use of gloves or masks, forgetting to wash hands before eating, or sticking one's fingers into one's nose or mouth, I will take an extra zinc lozenge and use the Sterimar spray in both my nose and in my mouth and throat.
The Food and Supplement Guide for the Coronavirus has now been updated to version 2.0, reflecting my research through today, April 2, 2020. It contains these revisions of the protocol, as well as more detail on how to implement it. Right now I'm able to publish this newsletter on a daily basis because sales of the guide allow me to devote myself to full-time research on COVID-19. I am comprehensively reading all the titles of preprints and published papers on COVID-19, stopping to read abstracts or full papers where I find them likely to have practical relevance, as well as keyword searching intensively for specific topics I will comprehensively review on this list, such as ACE2 and the mechanisms of the cytokine storm. If you would like to purchase a copy of the guide, you will help make it possible for me to continue doing this research, and I will be very grateful for that.
Stay safe,
Chris
Two new studies published today as preprints suggest that SARS-CoV-2, the coronavirus that causes COVID-19, infects the nose and causes anosmia, the loss of a sense of smell, by damaging the nerves.
Preprints are papers that are destined for peer-reviewed journals but have not yet been peer reviewed. The vast majority of reliable information circulating about COVID-19 is coming from preprints.
The first paper used isolated human airway epithelia. Epithelia are the layers of cells that line the surfaces of all our organs. In this case, the airway epithelia included layers from the bronchus (the airway that branches off from the windpipe to feed the lungs) and from the nose.
The researchers isolated SARS-CoV-2 from a nasal swab and used it to infect the airway epithelia. The infection developed faster in the bronchial cells than in the nasal cells, and reached a higher peak in the bronchial cells, but the infection nevertheless rapidly infected both types of cells.
I predicted SARS-CoV-2 would infect the nose yesterday. I predicted this on the basis of two main pieces of evidence. First, the paper showing it infected the throat used oropharyngeal swabs and nasopharyngeal swabs. Oropharyngeal swabs reach the throat through the mouth and nasopharyngeal swabs reach the throat through the nose. There was no difference in viral load between the two swabs. So, either it's all coming from the throat, which was emphasized in the paper, or it's equally coming from the nose and mouth in addition to the throat.
The second point is that ACE2 expression is the primary determinant of whether a cell can be infected. A 2004 paper showed that the epithelia of the nose, mouth, and throat do express ACE2, but they do so under the surface, on the basolateral side of the cell that is hidden from the environment, rather than on the apical surface, which faces the environment. They suggested that SARS-CoV, the closely related predecessor of SARS-CoV-2, would not be able to infect these tissues since the virus would not have access to the underside of the cell while entering the nose and mouth from the environment. However, if the throat can be infected, that probably means that the viruses easily slip between the cells to gain access to the ACE2 on their undersides, in which case they should do so just as easily in the nose and mouth.
This underscores my suggestion yesterday to use a copper-based nasal spray for prevention before and after potential exposure events. (Unfortunately, the spray I suggested sold out on Amazon yesterday; I will contact the company and see if I can get them to ramp up their Amazon supply).
In this study, the virus primarily replicated in goblet cells, which produce mucous, and ciliated cells, which use hairlike projections called “cilia” to move mucous and debris. This is highly consistent with the study I wrote about Wednesday morning, showing that, in the lung, ACE2 is mostly expressed in ciliated cells and goblet cells, and that smoking strongly increases the amount of ACE2 expressed in the lung by dramatically increasing the number of mucous-producing goblet cells.
While the first paper dealt with the respiratory cells of the nose, the cells that contribute to our ability to breath and to filter, warm, and moisten the air we breath, the second study dealt with cells involved in our ability to smell. Patients and medical personnel are widely reporting that COVID-19 frequently causes reversible anosmia, a temporary loss of smell. Could this be from the virus causing nerve damage?
The nose is full of sensory neurons, which carry information from odor-carrying chemicals (odorants) to the brain, where our brain synthesizes the information to create the perception of smell. Each neuron has long branches called dendrites that are responsible for collecting the information carried by odorants. The dendrites have long cilia (again, the hair-like projections) that project into the mucous of the nasal passages with odorant receptors. The dendrites are each wrapped in supportive cells known as sustentacular cells. The sustentacular cells create the thick outer layer of what known as the neuroepithelium, the whole complex of cells needed to sense smells, and they are in direct contact with the outer environment.
If the sustentacular cells die, the whole neuroepithelium degenerates, and this is often the cause of anosmia.
The researchers didn't study live infections, but they assessed the vulnerability of the cells to SARS-CoV-2 infection by looking for two proteins. The first is ACE2, the protein that the virus first binds to with its own “spike” protein in order to attach to the cell. The second is an enzyme known as “transmembrane protease, serine 2” and abbreviated TMPRSS2. This enzyme processes the viral spike protein in a way that enables the virus to fuse with the cell membrane. Both of these events are required for the virus to enter the cell.
They reasoned that any cells expressing both ACE2 and TMPRSS2 in the cell membrane will be vulnerable to infection.
Olfactory neurons had little or no expression of either protein.
A variety of other cells expressed low levels of the two proteins.
The sustentacular cells, however, expressed high levels of both proteins. In fact, they expressed the two proteins at levels that are similar to those expressed in respiratory ciliated cells. This suggests that the sustentacular cells are just as likely to be infected as the ciliated cells and goblet cells of the airway, whose vulnerability to infection was shown directly in the first study.
Altogether, these two brand new papers, hot off the press, suggest that the virus is likely to be directly infecting the nose, focused on the mucous-producing cells and ciliated cells of the airway, and the sustentacular cells of the epithelium.
The direct attack on the sustentacular cells is probably what is causing the widely reported reversible loss of the sense of smell.
Stay safe,
Chris
Preprints are papers that are destined for peer-reviewed journals but have not yet been peer reviewed. The vast majority of reliable information circulating about COVID-19 is coming from preprints.
The first paper used isolated human airway epithelia. Epithelia are the layers of cells that line the surfaces of all our organs. In this case, the airway epithelia included layers from the bronchus (the airway that branches off from the windpipe to feed the lungs) and from the nose.
The researchers isolated SARS-CoV-2 from a nasal swab and used it to infect the airway epithelia. The infection developed faster in the bronchial cells than in the nasal cells, and reached a higher peak in the bronchial cells, but the infection nevertheless rapidly infected both types of cells.
I predicted SARS-CoV-2 would infect the nose yesterday. I predicted this on the basis of two main pieces of evidence. First, the paper showing it infected the throat used oropharyngeal swabs and nasopharyngeal swabs. Oropharyngeal swabs reach the throat through the mouth and nasopharyngeal swabs reach the throat through the nose. There was no difference in viral load between the two swabs. So, either it's all coming from the throat, which was emphasized in the paper, or it's equally coming from the nose and mouth in addition to the throat.
The second point is that ACE2 expression is the primary determinant of whether a cell can be infected. A 2004 paper showed that the epithelia of the nose, mouth, and throat do express ACE2, but they do so under the surface, on the basolateral side of the cell that is hidden from the environment, rather than on the apical surface, which faces the environment. They suggested that SARS-CoV, the closely related predecessor of SARS-CoV-2, would not be able to infect these tissues since the virus would not have access to the underside of the cell while entering the nose and mouth from the environment. However, if the throat can be infected, that probably means that the viruses easily slip between the cells to gain access to the ACE2 on their undersides, in which case they should do so just as easily in the nose and mouth.
This underscores my suggestion yesterday to use a copper-based nasal spray for prevention before and after potential exposure events. (Unfortunately, the spray I suggested sold out on Amazon yesterday; I will contact the company and see if I can get them to ramp up their Amazon supply).
In this study, the virus primarily replicated in goblet cells, which produce mucous, and ciliated cells, which use hairlike projections called “cilia” to move mucous and debris. This is highly consistent with the study I wrote about Wednesday morning, showing that, in the lung, ACE2 is mostly expressed in ciliated cells and goblet cells, and that smoking strongly increases the amount of ACE2 expressed in the lung by dramatically increasing the number of mucous-producing goblet cells.
While the first paper dealt with the respiratory cells of the nose, the cells that contribute to our ability to breath and to filter, warm, and moisten the air we breath, the second study dealt with cells involved in our ability to smell. Patients and medical personnel are widely reporting that COVID-19 frequently causes reversible anosmia, a temporary loss of smell. Could this be from the virus causing nerve damage?
The nose is full of sensory neurons, which carry information from odor-carrying chemicals (odorants) to the brain, where our brain synthesizes the information to create the perception of smell. Each neuron has long branches called dendrites that are responsible for collecting the information carried by odorants. The dendrites have long cilia (again, the hair-like projections) that project into the mucous of the nasal passages with odorant receptors. The dendrites are each wrapped in supportive cells known as sustentacular cells. The sustentacular cells create the thick outer layer of what known as the neuroepithelium, the whole complex of cells needed to sense smells, and they are in direct contact with the outer environment.
If the sustentacular cells die, the whole neuroepithelium degenerates, and this is often the cause of anosmia.
The researchers didn't study live infections, but they assessed the vulnerability of the cells to SARS-CoV-2 infection by looking for two proteins. The first is ACE2, the protein that the virus first binds to with its own “spike” protein in order to attach to the cell. The second is an enzyme known as “transmembrane protease, serine 2” and abbreviated TMPRSS2. This enzyme processes the viral spike protein in a way that enables the virus to fuse with the cell membrane. Both of these events are required for the virus to enter the cell.
They reasoned that any cells expressing both ACE2 and TMPRSS2 in the cell membrane will be vulnerable to infection.
Olfactory neurons had little or no expression of either protein.
A variety of other cells expressed low levels of the two proteins.
The sustentacular cells, however, expressed high levels of both proteins. In fact, they expressed the two proteins at levels that are similar to those expressed in respiratory ciliated cells. This suggests that the sustentacular cells are just as likely to be infected as the ciliated cells and goblet cells of the airway, whose vulnerability to infection was shown directly in the first study.
Altogether, these two brand new papers, hot off the press, suggest that the virus is likely to be directly infecting the nose, focused on the mucous-producing cells and ciliated cells of the airway, and the sustentacular cells of the epithelium.
The direct attack on the sustentacular cells is probably what is causing the widely reported reversible loss of the sense of smell.
Stay safe,
Chris
This post will probably be most helpful to physicians or other front-line health care professionals who are treating COVID-19 patients and have the ability to order lab tests.
Please note that I myself am not a physician or a health care professional. I'm just bringing you the research.
Recent research suggests that two readily available lab tests can predict who is at risk of a severe and potentially fatal COVID-19 outcome with stunning accuracy.
The first is a research letter published in the Nature journal Signal Transduction and Targeted Therapy. They found that low lymphocyte percentage strongly predicts whether someone with a severe case recovers or dies. They focus on the lymphocyte count at two time points:
While the day one lymphocyte count cannot categorize people neatly like the days 10-12 count or the days 17-19 count, we can say that a day one lymphocyte count of 25% virtually guarantees someone will not wind up in critical care, while a day one count of 15% or lower means they will have a severe case and may become critically ill.
While this is only based on 70 patients and larger studies would be needed to confirm how well this holds up in large populations, it suggests that measuring the lymphocyte count on the first day of symptoms could be a very useful predictor of whether someone will need serious treatment and whether they have a chance of needing critical care, and that the days 10-12 and 17-19 counts can be used to categorize patients with greater accuracy.
The second study used 36 patients and was published on Saturday as a preprint, which means it hasn't yet been peer-reviewed. The vast majority of influential information circulating on COVID-19 comes from preprints simply because the situation is evolving so rapidly and it takes so long to get something peer-reviewed.
This study found that interleukin-6 (IL-6) is an extremely effective predictor of whether someone will require ventilation.
Typical levels of IL-6 in a healthy person are 5-7 pg/mL or lower.
Figure 1 from this paper shows how IL-6 can be used both at first admission to the hospital, and, when measured over time, at peak level, to predict who will need mechanical ventilation. Upon first admission, a threshold of 15 pg/mL or higher would capture everyone who would eventually need ventilation, while also including many patients who would not. A threshold of 50 pg/mL would eliminate 95% of those who would not need ventilation, while only losing 23% of those that would.
IL-6 is even more useful if measured regularly. 93% of those who would go on to need ventilation had a peak IL-6 above 80 pg/mL, while only 4% of those who did not need ventilation had a peak IL-6 that high.
Everyone who went on to need ventilation had a peak IL-6 above 50 pg/mL, while only 17% of those who did not need ventilation had a peak IL-6 that high.
This suggests that IL-6 at hospital admission could help triage patients by predicting their need for ventilation, and that serial IL-6 measurements could be used to track the change in that likelihood over time. Again, larger studies will be needed to confirm how well this marker holds up in large populations.
Taken together, initial and serial measurements of lymphocyte counts and IL-6 are likely to be very useful for triaging patients and predicting outcomes.
Stay safe,
Chris
Please note that I myself am not a physician or a health care professional. I'm just bringing you the research.
Recent research suggests that two readily available lab tests can predict who is at risk of a severe and potentially fatal COVID-19 outcome with stunning accuracy.
The first is a research letter published in the Nature journal Signal Transduction and Targeted Therapy. They found that low lymphocyte percentage strongly predicts whether someone with a severe case recovers or dies. They focus on the lymphocyte count at two time points:
- 10-12 days after symptoms arose, someone with a lymphocyte count below 20% would become a severe case and someone with a lymphocyte count above 20% would not.
- On days 17-19 after symptoms arose, someone with a lymphocyte count below 5% would wind up in ICU and have a strong chance of dying within 12 days; someone with a count between 5-20%, by contrast, would recover.
While the day one lymphocyte count cannot categorize people neatly like the days 10-12 count or the days 17-19 count, we can say that a day one lymphocyte count of 25% virtually guarantees someone will not wind up in critical care, while a day one count of 15% or lower means they will have a severe case and may become critically ill.
While this is only based on 70 patients and larger studies would be needed to confirm how well this holds up in large populations, it suggests that measuring the lymphocyte count on the first day of symptoms could be a very useful predictor of whether someone will need serious treatment and whether they have a chance of needing critical care, and that the days 10-12 and 17-19 counts can be used to categorize patients with greater accuracy.
The second study used 36 patients and was published on Saturday as a preprint, which means it hasn't yet been peer-reviewed. The vast majority of influential information circulating on COVID-19 comes from preprints simply because the situation is evolving so rapidly and it takes so long to get something peer-reviewed.
This study found that interleukin-6 (IL-6) is an extremely effective predictor of whether someone will require ventilation.
Typical levels of IL-6 in a healthy person are 5-7 pg/mL or lower.
Figure 1 from this paper shows how IL-6 can be used both at first admission to the hospital, and, when measured over time, at peak level, to predict who will need mechanical ventilation. Upon first admission, a threshold of 15 pg/mL or higher would capture everyone who would eventually need ventilation, while also including many patients who would not. A threshold of 50 pg/mL would eliminate 95% of those who would not need ventilation, while only losing 23% of those that would.
IL-6 is even more useful if measured regularly. 93% of those who would go on to need ventilation had a peak IL-6 above 80 pg/mL, while only 4% of those who did not need ventilation had a peak IL-6 that high.
Everyone who went on to need ventilation had a peak IL-6 above 50 pg/mL, while only 17% of those who did not need ventilation had a peak IL-6 that high.
This suggests that IL-6 at hospital admission could help triage patients by predicting their need for ventilation, and that serial IL-6 measurements could be used to track the change in that likelihood over time. Again, larger studies will be needed to confirm how well this marker holds up in large populations.
Taken together, initial and serial measurements of lymphocyte counts and IL-6 are likely to be very useful for triaging patients and predicting outcomes.
Stay safe,
Chris
If you lose your sense of smell, what are the chances you have COVID-19?
A new study released today as a preprint suggests that if you lose your sense of taste or smell, you have a 61.7% chance of having COVID-19.
Preprints are studies destined for peer-reviewed journals that have yet to be peer-reviewed. Because COVID-19 is such a rapidly evolving disease and peer-review takes so long, most of the information circulating about the disease comes from preprints.
The 61.7% figure is a lot higher than the 5.3% chance predicted by having flu-like symptoms, as I reported on April 1. It might be inflated, though, so let's consider how they arrived at it.
On March 24th, Zoe Global Limited and King's College London released the COVID RADAR Symptom Tracker app in the UK. Between March 24th and March 29th, 1,573,103 people signed up.
26% of people reported one or more COVID-19 symptom. From among them:
Overall, someone who had lost their sense of smell or taste had a 61.7% chance of testing positive.
When the researchers combined all of the symptoms into a prediction model, the loss of taste or smell was about twice as important as a fever, 3.5 times as important as a loss of appetite, five times as important as a cough or diarrhea, and more than six times as important as fatigue.
We should be cautious about putting too much emphasis on the 61.7% likelihood. The 1702 people who got tested were not randomly selected from the app participants. Instead, they got tested for reasons unrelated to the study: they had compelling symptoms, or they were in contact with someone infected, or they traveled to a high-risk area. These 1702 people probably had a significantly higher risk of being infected than the average person using the app. The app-users themselves were not a random sample of the population, and were biased towards younger individuals and females.
Nevertheless, there is no particular reason to think the study was biased towards associating the loss of the sense of smell or taste with COVID-19. They found that, among those who had other COVID-19-related symptoms, having this one symptom increased the odds of a positive test by 3-fold.
Still, no one has every single symptom, and just over 40% of those who tested positive in this study had not experienced any loss of their sense of taste or smell.
We won't know the true predictive value of these symptoms until they are applied to random samples of the population that have not yet been tested. However, to loosely put some numbers on it, I would think of it like this:
Stay safe,
Chris
A new study released today as a preprint suggests that if you lose your sense of taste or smell, you have a 61.7% chance of having COVID-19.
Preprints are studies destined for peer-reviewed journals that have yet to be peer-reviewed. Because COVID-19 is such a rapidly evolving disease and peer-review takes so long, most of the information circulating about the disease comes from preprints.
The 61.7% figure is a lot higher than the 5.3% chance predicted by having flu-like symptoms, as I reported on April 1. It might be inflated, though, so let's consider how they arrived at it.
On March 24th, Zoe Global Limited and King's College London released the COVID RADAR Symptom Tracker app in the UK. Between March 24th and March 29th, 1,573,103 people signed up.
26% of people reported one or more COVID-19 symptom. From among them:
- 11% had fever
- 29% had a persistent cough
- 28.2% had shortness of breath
- 53.1% had fatigue
- 18.2% had a loss of the sense of smell or taste.
Overall, someone who had lost their sense of smell or taste had a 61.7% chance of testing positive.
When the researchers combined all of the symptoms into a prediction model, the loss of taste or smell was about twice as important as a fever, 3.5 times as important as a loss of appetite, five times as important as a cough or diarrhea, and more than six times as important as fatigue.
We should be cautious about putting too much emphasis on the 61.7% likelihood. The 1702 people who got tested were not randomly selected from the app participants. Instead, they got tested for reasons unrelated to the study: they had compelling symptoms, or they were in contact with someone infected, or they traveled to a high-risk area. These 1702 people probably had a significantly higher risk of being infected than the average person using the app. The app-users themselves were not a random sample of the population, and were biased towards younger individuals and females.
Nevertheless, there is no particular reason to think the study was biased towards associating the loss of the sense of smell or taste with COVID-19. They found that, among those who had other COVID-19-related symptoms, having this one symptom increased the odds of a positive test by 3-fold.
Still, no one has every single symptom, and just over 40% of those who tested positive in this study had not experienced any loss of their sense of taste or smell.
We won't know the true predictive value of these symptoms until they are applied to random samples of the population that have not yet been tested. However, to loosely put some numbers on it, I would think of it like this:
- If adding this symptom to the more traditional ones triples the risk of a positive test, and if flu-like symptoms in Los Angeles back in mid-March when COVID-19 was far less common there indicated a 5.3% risk, then we might imagine that the lower bound of the predictive value of this symptom is 16%.
- We can take the current study, likely biased towards reporting a higher risk, as representing the upper bound at 62%.
Stay safe,
Chris
Two days ago, Seattle-based public health researchers released a new study as a preprint* suggesting that COVID-19 cases spread throughout communities within Washington state for 4-6 weeks before the first community-acquired case had been identified.
This is deeply concerning, because it suggests that by the time the first case is identified in a community it has already gained too strong a foothold to stop the spread through self-isolation of the people who have been diagnosed or have symptoms.
On January 19, 2020, one individual was identified in Washington state who had traveled to Wuhan and contracted the disease.
The first community-acquired case was not identified in Washington state until February 28.
SARS-CoV-2, the coronavirus that causes COVID-19, develops a genetic mutation about once every fifteen days. This allows researchers to compare the genomes of different samples and build an evolutionary tree.
They analyzed 326 genomes, and found that 85% of them fell into a closely related group known as a “clade” that most likely shared the January 19 case as a common ancestor.
When calculated based on the evolutionary tree alone, the median estimate for the first spread from the common ancestor is February 1, with 95% confidence that it occurred some time between January 18 and February 9. This is consistent with the January 19 case being the common ancestor, but it cannot rule out other possibilities. For example, the January 19 case could have been closely related to a different unknown case that arrived in Washington in the weeks that followed and began the spread.
Their results also suggest that in the weeks before the first community-acquired case was detected, the number of cases doubled every 2.4-5.1 days, with a median estimate of doubling every 3.4 days.
Seven genomes from the Grand Princess cruise ship were sampled, and all fall into the same clade. Their results cannot rule out that someone from the cruise ship started the Washington outbreak, but the authors consider it more likely that someone from the Washington outbreak brought it to the cruise ship.
These results suggest that by the time COVID-19 is identified in a community, it has already been spreading for 3-4 weeks and doubling every few days. This is particularly concerning because, as a Vox article from ten days ago pointed out, rural communities are likely to get hit later, but harder. The virus will spread much more quickly in somewhere like New York City, but NYC has lots of hospitals, health care workers, organizational infrastructure, and political clout. Many small communities have none of these things.
This makes a strong case for being proactive about hygiene and social distancing (and, in my opinion, antiviral nutrition and immune support) even if you live in a community that doesn't appear to have been hit yet, or that was hit recently but where things don't seem to be that bad.
Stay safe,
Chris
This is deeply concerning, because it suggests that by the time the first case is identified in a community it has already gained too strong a foothold to stop the spread through self-isolation of the people who have been diagnosed or have symptoms.
On January 19, 2020, one individual was identified in Washington state who had traveled to Wuhan and contracted the disease.
The first community-acquired case was not identified in Washington state until February 28.
SARS-CoV-2, the coronavirus that causes COVID-19, develops a genetic mutation about once every fifteen days. This allows researchers to compare the genomes of different samples and build an evolutionary tree.
They analyzed 326 genomes, and found that 85% of them fell into a closely related group known as a “clade” that most likely shared the January 19 case as a common ancestor.
When calculated based on the evolutionary tree alone, the median estimate for the first spread from the common ancestor is February 1, with 95% confidence that it occurred some time between January 18 and February 9. This is consistent with the January 19 case being the common ancestor, but it cannot rule out other possibilities. For example, the January 19 case could have been closely related to a different unknown case that arrived in Washington in the weeks that followed and began the spread.
Their results also suggest that in the weeks before the first community-acquired case was detected, the number of cases doubled every 2.4-5.1 days, with a median estimate of doubling every 3.4 days.
Seven genomes from the Grand Princess cruise ship were sampled, and all fall into the same clade. Their results cannot rule out that someone from the cruise ship started the Washington outbreak, but the authors consider it more likely that someone from the Washington outbreak brought it to the cruise ship.
These results suggest that by the time COVID-19 is identified in a community, it has already been spreading for 3-4 weeks and doubling every few days. This is particularly concerning because, as a Vox article from ten days ago pointed out, rural communities are likely to get hit later, but harder. The virus will spread much more quickly in somewhere like New York City, but NYC has lots of hospitals, health care workers, organizational infrastructure, and political clout. Many small communities have none of these things.
This makes a strong case for being proactive about hygiene and social distancing (and, in my opinion, antiviral nutrition and immune support) even if you live in a community that doesn't appear to have been hit yet, or that was hit recently but where things don't seem to be that bad.
Stay safe,
Chris
Whether pets such as cats and dogs can get COVID-19 is a subject of emerging controversy. Just today, a preprint* originally released on March 31 suggesting pets can be infected was published in Science. On the other hand, a new preprint was released today suggesting domestic pets under typical domestic circumstances are not being infected.
A variety of anecdotes have circulated suggesting animals can be infected. Tim Ferriss seemed to suggest his dog got infected at the end of an interview with former US Surgeon General Vivek Murthy, author of the new book, Together: The Healing Power of Connection in a Sometimes Lonely World. More recently, a tiger at the Bronx Zoo tested positive.
Let's take a closer look.
Experimental Infection of Cats, Dogs, and Ferrets
In the paper published in Science today, researchers experimentally infected various animals, including common pet and farm animals, through either the nose or throat, in some cases tested the animals' abilities to transmit the virus between each other, and after a period of time euthanized the animals and tested a wide variety of organs for signs of infection.
Whether ferrets were infected through the nose or throat, the virus replicated only in the upper respiratory tract: in the nose, soft palate (the back of the roof of the mouth), and the tonsils. No evidence of the virus was found in their lungs, heart, liver, spleen, kidneys, pancreas, small intestine, or brain, though low levels were found in some of the stool samples. One out of three ferrets developed fever and loss of appetite 10-12 days after infection. They had immune cells known as neutrophils and macrophages in their lungs, mild inflammation of the bronchi (the passages that lead from the windpipe to the lungs), and severe inflammation of the blood vessels and surrounding tissues.
In young adult outbred cats aged 6-9 months, the virus infected the soft palate, tonsils, trachea (“windpipe”), lungs, and small intestines. The virus was consistently found in their stool. Three cats were exposed to an inoculated partner by being kept in an adjacent cage separated by a double-layered net, and one of them became infected. This suggests that young adult cats can not only become infected but can also transmit the disease to other cats through the air.
In kittens aged 70-100 days, the pattern of infection was similar and they had “massive lesions” in the tissues of their nose, windpipe, and lungs.
In 3-month-old beagles, some of the dogs had some virus detected in their stool and developed antibodies to the virus, but none of them had evidence of viral replication in any of their internal organs.
Pigs, chickens, and ducks couldn't be infected.
14% of Cats in Pet Hospitals and Animal Shelters Got Infected in Wuhan
In a preprint released on April 3, researchers reported collecting serum samples from 102 cats in Wuhan's animal shelters and pet hospitals. Fifteen cats had antibodies to SARS-CoV-2, the coronavirus that causes COVID-19. Six were stray cats, and three were from owners who were confirmed as COVID-19 cases.
When the serum was mixed with SARS-COV-2-infected cells, the samples from cats with COVID-19-confirmed owners were most effective at neutralizing the virus, while some of the samples from the stray cats were not able to neutralize the virus despite the presence of antibodies. This suggests that exposure to their infected owners allowed the cats to develop more specific and more effective antibodies.
The authors did not report the breed or ages of the cats, which is important since the Science paper discussed above only looked at young cats, and the kittens seemed to have greater damage done to their tissues than the young adults. They also did not report details of how the animals interacted with humans and how they may have been exposed.
Cats and Dogs in Close Contact with French COVID-19 Owners
In a preprint released today, researchers looked at whether cats and dogs had been infected after being in close contact with COVID-19-confirmed owners.
Among 18 owners of 9 cats and 12 dogs who were members of a community associated with a French veterinary campus, 11 developed symptoms of COVID-19 and 2 got tested and were confirmed.
All of them lived in the same room with their pets. All of the cats and one-third of the dogs shared their owners' beds. 78% of cat owners and 92% of dog owners accepted face and hand licking.
The cats were all domestic European Shorthair cats between 6 months and 6.5 years old, with an average age of 3.3 years. 6 of the dogs were crossbred and 6 belonged to breeds including Labrador Retriever, Shetland Sheepdog, Belgian Malinois, and White Swiss Shepherd. The dogs ranged in age from 4 months to 8 years, with an average age of 2.7 years.
For the most part the animals were not sick, but three of the cats had respiratory or digestive signs that could be considered consistent with COVID-19.
No antibodies to the virus were found in the blood of any of the animals, and nasal and rectal swabs failed to show evidence of any infections.
Comparing the Results of the Three Studies
If we take the 14.7% infection rate in Wuhan cats as a benchmark, we would only expect to find one infected cat among the nine tested in the French study. Under these assumptions, the sample size was just too low in the French study to protect against a false negative.
On the other hand, we know virtually nothing about the degree of exposure of the Wuhan cats. We know the owners of the French study were co-sleeping and most were accepting face and hand licking. This might make the data in the Science paper a better benchmark, where one in three cats were infected by staying in close quarters with experimentally inoculated cats. In that case we would expect three of the cats to have gotten sick in the French paper. Indeed, exactly three cats had respiratory and digestive signs, but none tested positive.
Nevertheless, we still have some problems with the numbers:
Furthermore, the Science paper used kittens and young adult cats, and the older cats in the French study may be less vulnerable to infection.
The Bottom Line
Right now it appears that dogs have a very slight vulnerability to infection that may not be very consequential, while young adult cats are capable of getting mild infections and spreading the virus, and kittens are capable of getting very sick. This has only been shown under experimental conditions where the animals are directly inoculated through the nose or throat.
Almost nothing is known about how different breeds differ in their vulnerability to infection, and it remains unclear whether cats can be infected just from sharing rooms and licking the face or hands of an infected owner.
It does seem wise to protect kittens from any humans known to be sick with COVID-19, and to keep your face and hands well-washed regardless of whether you believe you have the virus if you have a kitten or young cat that licks them. Ferrets should be similarly protected. It is less clear whether these precautions need to be taken around dogs, and completely unknown whether they should be taken around most other pets.
However, given that good hygiene is already an important part of preventing spread between humans, it seems best to regard any pets as just another member of the household to be protected during this time.
Stay safe,
Chris
A variety of anecdotes have circulated suggesting animals can be infected. Tim Ferriss seemed to suggest his dog got infected at the end of an interview with former US Surgeon General Vivek Murthy, author of the new book, Together: The Healing Power of Connection in a Sometimes Lonely World. More recently, a tiger at the Bronx Zoo tested positive.
Let's take a closer look.
Experimental Infection of Cats, Dogs, and Ferrets
In the paper published in Science today, researchers experimentally infected various animals, including common pet and farm animals, through either the nose or throat, in some cases tested the animals' abilities to transmit the virus between each other, and after a period of time euthanized the animals and tested a wide variety of organs for signs of infection.
Whether ferrets were infected through the nose or throat, the virus replicated only in the upper respiratory tract: in the nose, soft palate (the back of the roof of the mouth), and the tonsils. No evidence of the virus was found in their lungs, heart, liver, spleen, kidneys, pancreas, small intestine, or brain, though low levels were found in some of the stool samples. One out of three ferrets developed fever and loss of appetite 10-12 days after infection. They had immune cells known as neutrophils and macrophages in their lungs, mild inflammation of the bronchi (the passages that lead from the windpipe to the lungs), and severe inflammation of the blood vessels and surrounding tissues.
In young adult outbred cats aged 6-9 months, the virus infected the soft palate, tonsils, trachea (“windpipe”), lungs, and small intestines. The virus was consistently found in their stool. Three cats were exposed to an inoculated partner by being kept in an adjacent cage separated by a double-layered net, and one of them became infected. This suggests that young adult cats can not only become infected but can also transmit the disease to other cats through the air.
In kittens aged 70-100 days, the pattern of infection was similar and they had “massive lesions” in the tissues of their nose, windpipe, and lungs.
In 3-month-old beagles, some of the dogs had some virus detected in their stool and developed antibodies to the virus, but none of them had evidence of viral replication in any of their internal organs.
Pigs, chickens, and ducks couldn't be infected.
14% of Cats in Pet Hospitals and Animal Shelters Got Infected in Wuhan
In a preprint released on April 3, researchers reported collecting serum samples from 102 cats in Wuhan's animal shelters and pet hospitals. Fifteen cats had antibodies to SARS-CoV-2, the coronavirus that causes COVID-19. Six were stray cats, and three were from owners who were confirmed as COVID-19 cases.
When the serum was mixed with SARS-COV-2-infected cells, the samples from cats with COVID-19-confirmed owners were most effective at neutralizing the virus, while some of the samples from the stray cats were not able to neutralize the virus despite the presence of antibodies. This suggests that exposure to their infected owners allowed the cats to develop more specific and more effective antibodies.
The authors did not report the breed or ages of the cats, which is important since the Science paper discussed above only looked at young cats, and the kittens seemed to have greater damage done to their tissues than the young adults. They also did not report details of how the animals interacted with humans and how they may have been exposed.
Cats and Dogs in Close Contact with French COVID-19 Owners
In a preprint released today, researchers looked at whether cats and dogs had been infected after being in close contact with COVID-19-confirmed owners.
Among 18 owners of 9 cats and 12 dogs who were members of a community associated with a French veterinary campus, 11 developed symptoms of COVID-19 and 2 got tested and were confirmed.
All of them lived in the same room with their pets. All of the cats and one-third of the dogs shared their owners' beds. 78% of cat owners and 92% of dog owners accepted face and hand licking.
The cats were all domestic European Shorthair cats between 6 months and 6.5 years old, with an average age of 3.3 years. 6 of the dogs were crossbred and 6 belonged to breeds including Labrador Retriever, Shetland Sheepdog, Belgian Malinois, and White Swiss Shepherd. The dogs ranged in age from 4 months to 8 years, with an average age of 2.7 years.
For the most part the animals were not sick, but three of the cats had respiratory or digestive signs that could be considered consistent with COVID-19.
No antibodies to the virus were found in the blood of any of the animals, and nasal and rectal swabs failed to show evidence of any infections.
Comparing the Results of the Three Studies
If we take the 14.7% infection rate in Wuhan cats as a benchmark, we would only expect to find one infected cat among the nine tested in the French study. Under these assumptions, the sample size was just too low in the French study to protect against a false negative.
On the other hand, we know virtually nothing about the degree of exposure of the Wuhan cats. We know the owners of the French study were co-sleeping and most were accepting face and hand licking. This might make the data in the Science paper a better benchmark, where one in three cats were infected by staying in close quarters with experimentally inoculated cats. In that case we would expect three of the cats to have gotten sick in the French paper. Indeed, exactly three cats had respiratory and digestive signs, but none tested positive.
Nevertheless, we still have some problems with the numbers:
- In the Science paper, only three cats were paired up with an inoculated partner, and only one got sick. The sample size is too small to determine the rate of transmission.
- In the French paper, only two of eleven owners got tested for COVID-19. As I reported here and here, the likelihood someone with flu-like symptoms has COVID-19 is close to 5%, and this is increased to probably somewhere between 16 and 62% if they also lose their sense of smell or taste. The French paper did not report any of the specific symptoms the pet owners had, so it's not clear how many of the nine owners with symptoms and no testing actually had COVID-19.
Furthermore, the Science paper used kittens and young adult cats, and the older cats in the French study may be less vulnerable to infection.
The Bottom Line
Right now it appears that dogs have a very slight vulnerability to infection that may not be very consequential, while young adult cats are capable of getting mild infections and spreading the virus, and kittens are capable of getting very sick. This has only been shown under experimental conditions where the animals are directly inoculated through the nose or throat.
Almost nothing is known about how different breeds differ in their vulnerability to infection, and it remains unclear whether cats can be infected just from sharing rooms and licking the face or hands of an infected owner.
It does seem wise to protect kittens from any humans known to be sick with COVID-19, and to keep your face and hands well-washed regardless of whether you believe you have the virus if you have a kitten or young cat that licks them. Ferrets should be similarly protected. It is less clear whether these precautions need to be taken around dogs, and completely unknown whether they should be taken around most other pets.
However, given that good hygiene is already an important part of preventing spread between humans, it seems best to regard any pets as just another member of the household to be protected during this time.
Stay safe,
Chris
On March 23, Dr. Zev Zelenko wrote an open letter “to medical professionals all around the world” about his treatment for COVID-19 using hydroxychloroquine, azithromycin, and zinc sulfate. Days before, he had addressed a YouTube video to President Trump about his success, which went viral and got picked up by many political commentators. This Wednesday Trump said at a briefing “you should add zinc” to any COVID-19 treatment, which has zinc all over the news right now.
I count myself among the advocates for zinc, and my protocol in The Food and Supplement Guide for the Coronavirus, supplies 46-78 milligrams of zinc per day, depending on how it's implemented, with an extra 36 milligrams of zinc around each potential exposure to the virus, and then additional zinc added for anyone experiencing any symptoms of cold, flu, or COVID-19. Someone who uses a typical zinc supplement and the recommended zinc lozenges, and goes out to the store once a day, would wind up getting 114 milligrams of zinc.
On the lower end, functional medicine mogul Dr. Mark Hyman recommends 20 milligrams per day of zinc. On the higher end, Zelenko's protocol includes 240 milligrams per day.
These are all significantly higher than the RDA of 11 mg/d for adult men and 8 mg/d for adult women. However, there is more than a ten-fold spread between these recommendations.
In this update, I'll be covering two questions:
Zelenko's rationale for zinc was as follows “We know that hydroxychloroquine helps Zinc enter the cell. We know that Zinc slows viral replication within the cell.”
Actually, we know neither of these things. As I pointed out in past updates, hydroxychloroquine and chloroquine have not been shown to bring zinc into cells at concentrations anywhere near as low those required to stop the replication of SARS-CoV-2, the virus that causes COVID-19. Moreover, at the high concentrations needed to bring zinc into the cell, they keep it stuck in locations of the cell that would be irrelevant to slowing viral replication. Further, there is as yet no direct evidence that zinc slows the replication of the virus.
Here is what we do know.
Zinc directly inhibits two enzymes essential to the replication of SARS-CoV, the coronavirus that causes SARS. These include papain-like protease 2 (PLP2) and the 3CL protease. The sequences and structures of these enzymes are similar to the corresponding enzymes of SARS-CoV-2 (documented here, and here). These are enzymes known as “cysteine proteases,” which use sulfur from the amino acid cysteine to carry out their work. Zinc binds to the cysteine to inhibit them. This particular aspect of the enzymes is completely the same between SARS-CoV and SARS-CoV-2. Therefore, zinc almost certainly inhibits the enzymes within SARS-CoV-2.
Does that mean it slows viral replication?
It means it could.
One of the main determinants is what concentration of zinc will be available to inhibit the enzymes, and what concentration would be required to do so.
The studies looking at the inhibitory effect of zinc on these enzymes use ionic zinc, which is freely available and not bound to anything else. They also use purified enzymes. They show that zinc inhibits these enzymes by 50% when its concentration is is one micromole per liter, a measure of how many atoms or molecules are present in a liter, abbreviated here as uM.
In a living organism, however, the enzymes are not purified, nor is the zinc mostly ionic. The enzymes are found embedded in the membrane of the cell's primary protein-producing factory, known as the endoplasmic reticulum. The part of the enzymes that are inhibited by zinc face the cytosol, which is the main compartment of the cell. While the concentration of zinc required to inhibit the enzymes in their purified state is 1 uM, I suspect it is lower when they are embedded in the membrane because the membrane will help hold them in place and orient them toward the zinc. My suspicion is it might cut the concentration required in half, to 0.5 uM (which is 500 nanomolar, or nM).
Is there enough zinc in the cytosol to inhibit these enzymes?
The answer depends on how we think about it. On the one hand, the total cytosolic zinc is hundreds of micromolar, which is hundreds of times higher than what is needed to inhibit the enzymes. On the other hand, only hundreds of picomolar of zinc are ionized in the cell at any given moment. That's about 1,000 times lower than what is needed to inhibit these enzymes. Still, about 30 times as much zinc as is ionized in any given instant is loosely bound to proteins, and will very rapidly free itself to replenish ionic zinc pools. Even larger amounts of zinc can be freed over the course of hours or days by degrading the zinc storage proteins within the cell and not replacing them. So, in theory, there are hundreds of micromolar zinc available that could be freed to inhibit the viral replication enzymes, but will they?
That really depends on whether cellular zinc proteins have all they need:
That will not be achieved with hydroxyhloroquine or chloroquine. As noted above, they trap zinc in other locations of the cell that are irrelevant to viral replication. As I will discuss below, the best chance of achieving this is with appropriately dosed zinc supplements.
Clinical Evidence Supporting the Antiviral Activity of Zinc
At this time, there is no clear clinical evidence that zinc has a specific application for COVID-19. Zelenko's protocol may work, but it hasn't been tested in a randomized controlled trial, and if we assume it works, we still don't know which component works best, if they are all needed in combination, or whether the doses chosen are best.
The clearest clinical evidence that zinc has antiviral properties in humans comes from the use of zinc lozenges to treat the common cold (reviewed here, here, and here.) These trials show that ≥75 mg/d zinc is necessary to have a useful effect. They supply the zinc using lozenges, and the zinc is in a form such as zinc acetate, zinc gluconate, or zinc gluconate glycine. Zinc acetate resulted in an average reduction of the duration of colds by 42%, while other forms of zinc resulted in an average reduction of 20%.
The rationale for zinc in the common cold is quite different from the rationale in COVID-19.
For the common cold, the primary mechanism of zinc is to prevent rhinoviruses from docking to their cellular receptor, ICAM-1. Since cold viruses infect the nose and throat, lozenges are used to increase the delivery to those tissues. This requires zinc to ionize outside of the relevant cells, and zinc acetate ionizes to a greater extent than other forms of zinc, which is why it is roughly twice as effective as other forms.
Since SARS-CoV-2 appears to start in the nose and throat, it does make sense to use zinc acetate lozenges to deliver zinc to those tissues. However, since the worst consequences occur in the lungs, it is also important to deliver zinc systemically so that the lung tissue becomes similarly enriched. This will only be achievable with high-dose oral zinc supplements that are swallowed, taken consistently over time prior to exposure to the virus.
What Is the Maximum Amount of Zinc We Can Get Into Our Bodies?
Our best chance at leveraging the antiviral activity of zinc systemically is to use the maximally useful, safe dose of zinc. When I say “maximally useful,” I mean zinc that actually gets incorporated into our tissues instead of our feces or urine.
So let's look at what that dose is.
When a single dose of zinc is taken, the amount absorbed increases with increasing doses from 2 to 15 milligrams, but then we hit the law of diminishing returns. At 15 milligrams, 9.5 milligrams are absorbed. At 20 milligrams, 11 milligrams are absorbed. At 30 milligrams, 11.2 milligrams are absorbed. That's right, of the 10 milligrams added as we go from 20 to 30, only 0.2 milligrams are absorbed. Mathematical modeling from this study suggests that it is impossible to absorb more than 13 milligrams of zinc in one sitting, no matter how high the dose.
A single dose of zinc is not actually the best way to understand this. When our intake of zinc increases, even from a single dose, within hours or possibly up to several days, we will lower the amount of zinc we can absorb from food or supplements. Studies that look at total zinc from food and supplements spread throughout the day over the course of several weeks suggest that maximal daily zinc absorption is 5-7 mg.
Those studies, however, only used intakes up to 18 milligrams zinc. A much longer study added 100 mg/d zinc sulfate against a background diet of 10 mg/d from food over the course an average of 307 days. This dose more than doubled the total zinc absorbed from 4.5 to 10.5 mg/d, and it increased total body stores of zinc by 37%.
This latter study was conducted in people who had smell and taste dysfunction. They had lower than average body stores of zinc, so they may have been better primed to soak up enough zinc to boost their total body stores than someone with very good zinc status.
It is also notable that 110 mg/d carried out over the better part of a year produces a daily zinc absorption that is roughly equivalent to what is absorbed from a single dose of 20 mg. Unfortunately, it didn't clarify whether the zinc was taken all at once or spread throughout the day.
Unfortunately, there is no clear data showing what happens to total zinc stores using doses between 20 mg and 110 mg over weeks, months, or a year. It is clear that 20 mg is insufficient to maximize zinc absorption over days or weeks, because 20 mg/d zinc intakes only produce 5-7 mg/d that are absorbed. Presumably, at least 40 mg/d would be needed to result in the absorption of 10 mg/d. While it is not clear that 110 mg/d is needed, it is true that the only study showing a way to get the average daily absorption as high as 10.5 mg/d over the long term used that dose.
An Effective Dosing Protocol
It seems likely that maximal zinc absorption, over the long-term, would be provided by a dose somewhere between 40 mg/d and 110 mg/d. We also know that zinc absorption is greater when the dose is spread out, and when it is not accompanied by sources of phytate, such as whole grains, nuts, seeds, and legumes). Therefore, I recommend maximizing zinc absorption as follows:
Too Much Zinc Hurts the Immune System
In one study, 300 mg/d of zinc as two divided doses of 150 mg zinc sulfate decreased important markers of immune function, such as the ability of immune cells known as polymorphonuclear leukocytes to migrate towards and consume bacteria. The most concerning effect in the context of COVID-19 is that it lowered the lymphocyte stimulation index 3-fold. This is a measure of the ability of T cells to increase their numbers in response to a perceived threat.
The reason this is so concerning in the context of COVID-19 is that poor outcomes are associated with low lymphocytes (see here, here, here, here, and here).
While 300 mg/d zinc did not lower lymphocyte counts, the fact that it lowered their ability to multiply in a lab dish suggests that such high doses could prime a person to have a poorer ability to maintain their lymphocyte count in a disease.
There are some suggestions that lower doses don't cause this problem:
The radiation study, in particular, is useful. Lymphocyte counts dropped more than three-fold in response to radiation therapy, and they recovered 63% in the first month following therapy. That zinc didn't hurt the recovery in any way suggests that 150 mg/d zinc does not hurt the ability of lymphocytes to proliferate under stress.
Although there are no studies showing people are actually more likely to get sick or experience worse illnesses on high-dose zinc, the negative effect on lymphocyte proliferation found with 300 mg/d and the apparent safety in this regard of 150 mg/d suggests that the potential for hurting the immune system may begin somewhere between 150-300 mg/d.
Zinc/Copper Balance Is Critical
It is quite possible that the harmful effect of 300 mg/d zinc on the lymphocyte stimulation index is mediated mostly or completely by induction of copper deficiency.
In fact, low-copper diets cause a decline in the stimulation index of peripheral blood mononuclear cells, which is a similar test.
The negative effect of zinc on copper status has been shown with as little as 60 mg/d zinc. This intake lowers the activity of superoxide dismutase, an enzyme important to antioxidant defense and immune function that depends both on zinc and copper. The zinc lowers copper status; as a result, the enzyme has enough zinc, but not enough copper; without both, it can't function, so it's activity declines.
A study done with relatively low intakes of zinc suggested that acceptable ratios of zinc to copper range from 2:1 to 15:1 in favor of zinc. Copper appears safe to consume up to a maximum of 10 mg/d. Notably, the maximum amount of zinc one could consume while staying in the acceptable range of zinc-to-copper ratios and also staying within the upper limit for copper is 150 mg/d.
As a result, when using zinc prophylactically for prevention of COVID-19, I suggest the following:
Other Potential Problems of High-Dose Zinc
Other adverse effects of zinc include gastrointestinal distress at 50-150 mg/d and stomach pain, nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, and headaches at 225-450 mg/d.
Zinc can interact with certain medications. It should be taken at least two hours away from the antibiotics cephalexin and penicillamine, the antiretroviral drugs atazanavir and ritonavir, tetracycline, and quinolone antibiotics.
The Bottom Line
While there are no randomized, controlled trials showing that zinc can prevent or treat COVID-19, zinc may well be able to slow replication of the virus.
The ideal dose for prevention while the COVID-19 risk is high is 40-110 mg/d, a portion of which comes from zinc lozenges to spread the zinc through the tissues of the nose, mouth and throat. It should be accompanied by at least 1 mg copper from food and supplements for every 15 mg zinc.
Zinc that is swallowed for the sake of reaching the lungs should be used preventatively rather than at the first sign of symptoms, because it takes a long time to enrich systemic stores of zinc.
I prefer to use 1-3 zinc lozenges per day preventatively so that the tissues of the nose and throat are rich in zinc as soon as they encounter the virus. Unlike swallowed zinc, however, lozenges designed to spread zinc through these tissues can be jacked up quickly in response to symptoms, because their ability to spread zinc through these tissues is not limited by intestinal zinc transporters.
Extra caution should be exercised with zinc intakes above 150 mg/d, as they carry some risk of hurting the immune system, especially when not balanced with copper.
Stay safe,
Chris
I count myself among the advocates for zinc, and my protocol in The Food and Supplement Guide for the Coronavirus, supplies 46-78 milligrams of zinc per day, depending on how it's implemented, with an extra 36 milligrams of zinc around each potential exposure to the virus, and then additional zinc added for anyone experiencing any symptoms of cold, flu, or COVID-19. Someone who uses a typical zinc supplement and the recommended zinc lozenges, and goes out to the store once a day, would wind up getting 114 milligrams of zinc.
On the lower end, functional medicine mogul Dr. Mark Hyman recommends 20 milligrams per day of zinc. On the higher end, Zelenko's protocol includes 240 milligrams per day.
These are all significantly higher than the RDA of 11 mg/d for adult men and 8 mg/d for adult women. However, there is more than a ten-fold spread between these recommendations.
In this update, I'll be covering two questions:
- How likely is zinc to help prevent or treat COVID-19?
- If it is effective, what is the best dose to take?
Zelenko's rationale for zinc was as follows “We know that hydroxychloroquine helps Zinc enter the cell. We know that Zinc slows viral replication within the cell.”
Actually, we know neither of these things. As I pointed out in past updates, hydroxychloroquine and chloroquine have not been shown to bring zinc into cells at concentrations anywhere near as low those required to stop the replication of SARS-CoV-2, the virus that causes COVID-19. Moreover, at the high concentrations needed to bring zinc into the cell, they keep it stuck in locations of the cell that would be irrelevant to slowing viral replication. Further, there is as yet no direct evidence that zinc slows the replication of the virus.
Here is what we do know.
Zinc directly inhibits two enzymes essential to the replication of SARS-CoV, the coronavirus that causes SARS. These include papain-like protease 2 (PLP2) and the 3CL protease. The sequences and structures of these enzymes are similar to the corresponding enzymes of SARS-CoV-2 (documented here, and here). These are enzymes known as “cysteine proteases,” which use sulfur from the amino acid cysteine to carry out their work. Zinc binds to the cysteine to inhibit them. This particular aspect of the enzymes is completely the same between SARS-CoV and SARS-CoV-2. Therefore, zinc almost certainly inhibits the enzymes within SARS-CoV-2.
Does that mean it slows viral replication?
It means it could.
One of the main determinants is what concentration of zinc will be available to inhibit the enzymes, and what concentration would be required to do so.
The studies looking at the inhibitory effect of zinc on these enzymes use ionic zinc, which is freely available and not bound to anything else. They also use purified enzymes. They show that zinc inhibits these enzymes by 50% when its concentration is is one micromole per liter, a measure of how many atoms or molecules are present in a liter, abbreviated here as uM.
In a living organism, however, the enzymes are not purified, nor is the zinc mostly ionic. The enzymes are found embedded in the membrane of the cell's primary protein-producing factory, known as the endoplasmic reticulum. The part of the enzymes that are inhibited by zinc face the cytosol, which is the main compartment of the cell. While the concentration of zinc required to inhibit the enzymes in their purified state is 1 uM, I suspect it is lower when they are embedded in the membrane because the membrane will help hold them in place and orient them toward the zinc. My suspicion is it might cut the concentration required in half, to 0.5 uM (which is 500 nanomolar, or nM).
Is there enough zinc in the cytosol to inhibit these enzymes?
The answer depends on how we think about it. On the one hand, the total cytosolic zinc is hundreds of micromolar, which is hundreds of times higher than what is needed to inhibit the enzymes. On the other hand, only hundreds of picomolar of zinc are ionized in the cell at any given moment. That's about 1,000 times lower than what is needed to inhibit these enzymes. Still, about 30 times as much zinc as is ionized in any given instant is loosely bound to proteins, and will very rapidly free itself to replenish ionic zinc pools. Even larger amounts of zinc can be freed over the course of hours or days by degrading the zinc storage proteins within the cell and not replacing them. So, in theory, there are hundreds of micromolar zinc available that could be freed to inhibit the viral replication enzymes, but will they?
That really depends on whether cellular zinc proteins have all they need:
- The highest-priority zinc proteins will bind zinc at low picomolar concentrations. They will never give up their zinc except in extreme deficiency.
- The lowest-priority zinc proteins will bind zinc at nanomolar concentrations. They only get zinc when the cell is replete.
- The viral replication proteins are inhibited at 1 micromolar, perhaps lower within the cell. Whatever the true inhibitory concentration is, it is certainly larger than needed to satisfy essential zinc-binding proteins, and it will only be available to inhibit viral replication when provided over and above what is needed for adequate nutritional status.
That will not be achieved with hydroxyhloroquine or chloroquine. As noted above, they trap zinc in other locations of the cell that are irrelevant to viral replication. As I will discuss below, the best chance of achieving this is with appropriately dosed zinc supplements.
Clinical Evidence Supporting the Antiviral Activity of Zinc
At this time, there is no clear clinical evidence that zinc has a specific application for COVID-19. Zelenko's protocol may work, but it hasn't been tested in a randomized controlled trial, and if we assume it works, we still don't know which component works best, if they are all needed in combination, or whether the doses chosen are best.
The clearest clinical evidence that zinc has antiviral properties in humans comes from the use of zinc lozenges to treat the common cold (reviewed here, here, and here.) These trials show that ≥75 mg/d zinc is necessary to have a useful effect. They supply the zinc using lozenges, and the zinc is in a form such as zinc acetate, zinc gluconate, or zinc gluconate glycine. Zinc acetate resulted in an average reduction of the duration of colds by 42%, while other forms of zinc resulted in an average reduction of 20%.
The rationale for zinc in the common cold is quite different from the rationale in COVID-19.
For the common cold, the primary mechanism of zinc is to prevent rhinoviruses from docking to their cellular receptor, ICAM-1. Since cold viruses infect the nose and throat, lozenges are used to increase the delivery to those tissues. This requires zinc to ionize outside of the relevant cells, and zinc acetate ionizes to a greater extent than other forms of zinc, which is why it is roughly twice as effective as other forms.
Since SARS-CoV-2 appears to start in the nose and throat, it does make sense to use zinc acetate lozenges to deliver zinc to those tissues. However, since the worst consequences occur in the lungs, it is also important to deliver zinc systemically so that the lung tissue becomes similarly enriched. This will only be achievable with high-dose oral zinc supplements that are swallowed, taken consistently over time prior to exposure to the virus.
What Is the Maximum Amount of Zinc We Can Get Into Our Bodies?
Our best chance at leveraging the antiviral activity of zinc systemically is to use the maximally useful, safe dose of zinc. When I say “maximally useful,” I mean zinc that actually gets incorporated into our tissues instead of our feces or urine.
So let's look at what that dose is.
When a single dose of zinc is taken, the amount absorbed increases with increasing doses from 2 to 15 milligrams, but then we hit the law of diminishing returns. At 15 milligrams, 9.5 milligrams are absorbed. At 20 milligrams, 11 milligrams are absorbed. At 30 milligrams, 11.2 milligrams are absorbed. That's right, of the 10 milligrams added as we go from 20 to 30, only 0.2 milligrams are absorbed. Mathematical modeling from this study suggests that it is impossible to absorb more than 13 milligrams of zinc in one sitting, no matter how high the dose.
A single dose of zinc is not actually the best way to understand this. When our intake of zinc increases, even from a single dose, within hours or possibly up to several days, we will lower the amount of zinc we can absorb from food or supplements. Studies that look at total zinc from food and supplements spread throughout the day over the course of several weeks suggest that maximal daily zinc absorption is 5-7 mg.
Those studies, however, only used intakes up to 18 milligrams zinc. A much longer study added 100 mg/d zinc sulfate against a background diet of 10 mg/d from food over the course an average of 307 days. This dose more than doubled the total zinc absorbed from 4.5 to 10.5 mg/d, and it increased total body stores of zinc by 37%.
This latter study was conducted in people who had smell and taste dysfunction. They had lower than average body stores of zinc, so they may have been better primed to soak up enough zinc to boost their total body stores than someone with very good zinc status.
It is also notable that 110 mg/d carried out over the better part of a year produces a daily zinc absorption that is roughly equivalent to what is absorbed from a single dose of 20 mg. Unfortunately, it didn't clarify whether the zinc was taken all at once or spread throughout the day.
Unfortunately, there is no clear data showing what happens to total zinc stores using doses between 20 mg and 110 mg over weeks, months, or a year. It is clear that 20 mg is insufficient to maximize zinc absorption over days or weeks, because 20 mg/d zinc intakes only produce 5-7 mg/d that are absorbed. Presumably, at least 40 mg/d would be needed to result in the absorption of 10 mg/d. While it is not clear that 110 mg/d is needed, it is true that the only study showing a way to get the average daily absorption as high as 10.5 mg/d over the long term used that dose.
An Effective Dosing Protocol
It seems likely that maximal zinc absorption, over the long-term, would be provided by a dose somewhere between 40 mg/d and 110 mg/d. We also know that zinc absorption is greater when the dose is spread out, and when it is not accompanied by sources of phytate, such as whole grains, nuts, seeds, and legumes). Therefore, I recommend maximizing zinc absorption as follows:
- Since it takes food about 4-6 hours to move through the stomach and 4-6 hours to move through the small intestine, I'm assuming the short-term saturation of zinc transporters resulting from the presence of zinc in food and supplements would be more or less “reset” every five hours.
- Aim for a total zinc intake of 40-110 mg/d, split evenly into doses that can be separated by 5 hours.
- Consume zinc supplements away from any meals containing whole grains, nuts, seeds, or legumes, whenever possible.
- Consume 7-15 mg zinc four times a day, spread out as much as possible.
- If possible, take it on an empty stomach. If that causes nausea, take it with some phytate-free food.
- Use one zinc acetate lozenge per day, providing an additional 18 mg zinc. Before and after any deliberate potential exposures to the virus, use an additional lozenge. If a potential exposure is an accident, use a lozenge afterwards.
Too Much Zinc Hurts the Immune System
In one study, 300 mg/d of zinc as two divided doses of 150 mg zinc sulfate decreased important markers of immune function, such as the ability of immune cells known as polymorphonuclear leukocytes to migrate towards and consume bacteria. The most concerning effect in the context of COVID-19 is that it lowered the lymphocyte stimulation index 3-fold. This is a measure of the ability of T cells to increase their numbers in response to a perceived threat.
The reason this is so concerning in the context of COVID-19 is that poor outcomes are associated with low lymphocytes (see here, here, here, here, and here).
While 300 mg/d zinc did not lower lymphocyte counts, the fact that it lowered their ability to multiply in a lab dish suggests that such high doses could prime a person to have a poorer ability to maintain their lymphocyte count in a disease.
There are some suggestions that lower doses don't cause this problem:
- Radiation therapy lowers lymphocyte counts. 150 mg zinc/d does not lower them any further or hurt the ability to recover them in patients with head and neck cancer.
- In patients with a parasitical infection known as leishmaniasis, 45 mg/d did not hurt the ability of peripheral blood mononuclear cells, a group that includes lymphocytes, to replicate in a stimulation index test.
- In HIV-infected patients with tuberculosis, 50 mg/d did not hurt lymphocyte counts.
- In patients with Crohn's disease, neither 60 mg/d nor 200 mg/d hurt lymphocyte counts.
The radiation study, in particular, is useful. Lymphocyte counts dropped more than three-fold in response to radiation therapy, and they recovered 63% in the first month following therapy. That zinc didn't hurt the recovery in any way suggests that 150 mg/d zinc does not hurt the ability of lymphocytes to proliferate under stress.
Although there are no studies showing people are actually more likely to get sick or experience worse illnesses on high-dose zinc, the negative effect on lymphocyte proliferation found with 300 mg/d and the apparent safety in this regard of 150 mg/d suggests that the potential for hurting the immune system may begin somewhere between 150-300 mg/d.
Zinc/Copper Balance Is Critical
It is quite possible that the harmful effect of 300 mg/d zinc on the lymphocyte stimulation index is mediated mostly or completely by induction of copper deficiency.
In fact, low-copper diets cause a decline in the stimulation index of peripheral blood mononuclear cells, which is a similar test.
The negative effect of zinc on copper status has been shown with as little as 60 mg/d zinc. This intake lowers the activity of superoxide dismutase, an enzyme important to antioxidant defense and immune function that depends both on zinc and copper. The zinc lowers copper status; as a result, the enzyme has enough zinc, but not enough copper; without both, it can't function, so it's activity declines.
A study done with relatively low intakes of zinc suggested that acceptable ratios of zinc to copper range from 2:1 to 15:1 in favor of zinc. Copper appears safe to consume up to a maximum of 10 mg/d. Notably, the maximum amount of zinc one could consume while staying in the acceptable range of zinc-to-copper ratios and also staying within the upper limit for copper is 150 mg/d.
As a result, when using zinc prophylactically for prevention of COVID-19, I suggest the following:
- Keep non-lozenge zinc equal to or less than 150 mg/d.
- Keep total zinc equal to or less than 150 mg/d except for short-term use of additional lozenges during illness.
- For every 15 milligrams of zinc, obtain at least one milligram of copper from foods and supplements.
Other Potential Problems of High-Dose Zinc
Other adverse effects of zinc include gastrointestinal distress at 50-150 mg/d and stomach pain, nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, and headaches at 225-450 mg/d.
Zinc can interact with certain medications. It should be taken at least two hours away from the antibiotics cephalexin and penicillamine, the antiretroviral drugs atazanavir and ritonavir, tetracycline, and quinolone antibiotics.
The Bottom Line
While there are no randomized, controlled trials showing that zinc can prevent or treat COVID-19, zinc may well be able to slow replication of the virus.
The ideal dose for prevention while the COVID-19 risk is high is 40-110 mg/d, a portion of which comes from zinc lozenges to spread the zinc through the tissues of the nose, mouth and throat. It should be accompanied by at least 1 mg copper from food and supplements for every 15 mg zinc.
Zinc that is swallowed for the sake of reaching the lungs should be used preventatively rather than at the first sign of symptoms, because it takes a long time to enrich systemic stores of zinc.
I prefer to use 1-3 zinc lozenges per day preventatively so that the tissues of the nose and throat are rich in zinc as soon as they encounter the virus. Unlike swallowed zinc, however, lozenges designed to spread zinc through these tissues can be jacked up quickly in response to symptoms, because their ability to spread zinc through these tissues is not limited by intestinal zinc transporters.
Extra caution should be exercised with zinc intakes above 150 mg/d, as they carry some risk of hurting the immune system, especially when not balanced with copper.
Stay safe,
Chris
A new preprint* released todayanalyzed data from the Diamond Princess Cruise Ship suggesting that SARS-CoV-2, the coronavirus that causes COVID-19, does not travel in the air very far.
This is important because it reinforces the safety of going outside, enjoying sunshine, and taking walks, as long as we keep 3-6 feet distance from others and follow the other hygiene and social distancing recommendations.
Background
A passenger joined this ship on January 20, who came down with a fever on January 23 that was confirmed on February 1 to be COVID-19. The ship was quarantined at sea on the morning of February 5, and the passengers were quarantined to their staterooms until February 19. Most of the staterooms had a maximum occupancy of four passengers. On March 1, the passengers and crew left the ship.
By March 5, 552 out of 2666 (21%) of the passengers had become infected, and 144 out of 1045 (14%) of the crew had become infected.
The researchers used the known incubation period of the virus and the date of onset of each case as determined by the development of symptoms in order to estimate when the infections occurred.
The Virus Spread in Two Waves
Beginning on January 28, there was a small wave of spread occurring in people who shared a stateroom and a much larger wave of spread occurring in people who did not share a stateroom. The large wave was overwhelmingly dominant and ended on February 5, reflecting the implementation of the quarantine.
The large wave was associated with a reproduction number (R-naught) of eleven, which is much higher than anyone has suggested for the virus in general. This is the number of people that one infected person can spread it to. The high reproductive number can easily be explained by the fact that a cruise ship has lots of people in tight spaces with plenty of opportunities for mass gatherings at pools, casinos, theaters, and so on.
After the quarantine, a second wave of transmission occurred in passengers who shared a stateroom, and in the crew. No second wave occurred in passengers who did not share a room.
This can be explained as follows:
Many of the staterooms had access to the open air via balcony doors.
The air in the staterooms themselves was connected by central AC, through which 70% of the air in the staterooms was indoor air and 30% was fresh outdoor air. The industry standards for the AC system suggest that air traveled at a rate of 8 liters per second, similar to the standards for office space.
If the virus were released into the open air and capable of traveling significant distances, it should have been able to travel from one stateroom to another through the AC system, and perhaps through the fresh air around the ship that came in and out of the stateroom balcony doors. That this did not happen suggests that the virus does not travel very far in the air.
The Bottom Line
This study reinforces the importance of avoiding mass gatherings, on the one hand, but reinforces the safety of the open air on the other. Staying inside all day is stressful and will have its own health toll. Going out in the sunshine and fresh air has physiological and psychological benefits, and is safe as long as we follow the recommended hygiene and social distancing norms.
Stay safe,
Chris
* The term “preprint” is often used in these updates. Preprints are studies destined for peer-reviewed journals that have yet to be peer-reviewed. Because COVID-19 is such a rapidly evolving disease and peer-review takes so long, most of the information circulating about the disease comes from preprints.
This is important because it reinforces the safety of going outside, enjoying sunshine, and taking walks, as long as we keep 3-6 feet distance from others and follow the other hygiene and social distancing recommendations.
Background
A passenger joined this ship on January 20, who came down with a fever on January 23 that was confirmed on February 1 to be COVID-19. The ship was quarantined at sea on the morning of February 5, and the passengers were quarantined to their staterooms until February 19. Most of the staterooms had a maximum occupancy of four passengers. On March 1, the passengers and crew left the ship.
By March 5, 552 out of 2666 (21%) of the passengers had become infected, and 144 out of 1045 (14%) of the crew had become infected.
The researchers used the known incubation period of the virus and the date of onset of each case as determined by the development of symptoms in order to estimate when the infections occurred.
The Virus Spread in Two Waves
Beginning on January 28, there was a small wave of spread occurring in people who shared a stateroom and a much larger wave of spread occurring in people who did not share a stateroom. The large wave was overwhelmingly dominant and ended on February 5, reflecting the implementation of the quarantine.
The large wave was associated with a reproduction number (R-naught) of eleven, which is much higher than anyone has suggested for the virus in general. This is the number of people that one infected person can spread it to. The high reproductive number can easily be explained by the fact that a cruise ship has lots of people in tight spaces with plenty of opportunities for mass gatherings at pools, casinos, theaters, and so on.
After the quarantine, a second wave of transmission occurred in passengers who shared a stateroom, and in the crew. No second wave occurred in passengers who did not share a room.
This can be explained as follows:
- Those who shared a stateroom had close contact with each other. This would potentially include coughing or sneezing, touching, talking face-to-face, and transmission across surfaces from respiratory secretions or fecal matter.
- The crew had to service the passengers and were in close contact with one another while working.
Many of the staterooms had access to the open air via balcony doors.
The air in the staterooms themselves was connected by central AC, through which 70% of the air in the staterooms was indoor air and 30% was fresh outdoor air. The industry standards for the AC system suggest that air traveled at a rate of 8 liters per second, similar to the standards for office space.
If the virus were released into the open air and capable of traveling significant distances, it should have been able to travel from one stateroom to another through the AC system, and perhaps through the fresh air around the ship that came in and out of the stateroom balcony doors. That this did not happen suggests that the virus does not travel very far in the air.
The Bottom Line
This study reinforces the importance of avoiding mass gatherings, on the one hand, but reinforces the safety of the open air on the other. Staying inside all day is stressful and will have its own health toll. Going out in the sunshine and fresh air has physiological and psychological benefits, and is safe as long as we follow the recommended hygiene and social distancing norms.
Stay safe,
Chris
* The term “preprint” is often used in these updates. Preprints are studies destined for peer-reviewed journals that have yet to be peer-reviewed. Because COVID-19 is such a rapidly evolving disease and peer-review takes so long, most of the information circulating about the disease comes from preprints.
I want nothing more than for the COVID-19 crisis to be over as fast as possible, but it's important to look carefully at the data and be realistic in order to do our best in arriving at a solution.
Several preprints* were released this weekend that, together, suggest three things:
Most Cases Are Undetected
Researchers from Harvard and MIT released a preprint estimating how many cases likely go undetected in the United States using data from Iceland.
The paper used data up through April 2, at which point almost 21,000 Icelanders, about 6% of the population, had been tested.
Iceland has two testing systems:
The deCODE testers were not a random sample of the population. In fact, 44% had symptoms of cold and flu, which is much higher than would be expected. As a result, the people who volunteered for testing were probably more likely to have COVID-19.
They dealt with this by performing several analyses, including one that excluded anyone with symptoms. When they did this, they estimated that at least 88.7% of COVID-19 cases go undetected by CDC criteria. When they included the people with cold and flu symptoms, they estimated that 92.5% of COVID-19 cases go undetected by CDC criteria.
These are similar to results published earlier from Wuhan suggesting CDC criteria would miss at least 85% of cases.
Overall these results suggest that only about one in ten cases of COVID-19 get detected in the United States.
Of course, the true rate would require testing in a random sample of the population. Such testing is underway in Iceland, Germany, and Norway.
For now, the one in ten figure makes sense.
Asymptomatics Can Transmit Infection
A researcher from the University of Aukland, New Zealand, released a review of papers documenting asymptomatic transmission.
He identified nine relevant papers. Most of them just document the existence of people who test positive for COVID-19 but do not have symptoms. One woman had lung damage from COVID-19, despite never experiencing symptoms. Several were asymptomatic yet had clusters of infected people in their family. 30-67% of people infected on the Diamond Princess cruise ship were asymptomatic.
These simply show that many people who are infected are asymptomatic. The most compelling case of transmission among those listed seems to be a woman from Shanghai who had no symptoms, but appeared to infect four people at a business meeting in Germany.
Personally, I find it very difficult to believe that asymptomatics cannot spread the infection. The Nature paper showing the virus infects the throatfound that viral loads in the throat were already declining on the first day of symptoms. People should be most infective when they have the highest viral loads in their body fluids. If the highest viral loads of the upper respiratory tract occur prior to the start of symptoms, it seems almost certain that people start spreading it before they have any symptoms.
72% of Counties in the US May Be Undergoing Outbreaks Right Now
A third preprint was released by researchers from the University of Texas at Austin.
These researchers estimated the likelihood that US counties had outbreaks right now that were below the radar of the community.
They made three key assumptions:
This suggests that the vast majority of US counties will have outbreaks if they don't have them already, and that many of the outbreaks that are brewing now will not materialize for another few weeks.
Using Ebola Data Suggests a Leveling Off, But Should We Use Ebola Data?
Two researchers from the University of Minnesota released a preprint where they suggested a leveling off was about to occur in the US. They used a statistical model that performed very well in predicting the leveling off of Ebola before it happened, and they assumed we are getting close to the flat top of an S-shaped curve. Here they show that China fits this data and the US is about to:
There are two problems I see with this approach:
Social Distancing Triggers the Transition From Exponential to Linear Growth
The fifth and final of this weekend's preprints I will review here is a paper released from researchers in India.
They suggest a model where the institution of strict social distancing transitions a society from a curve of exponential growth to a curve of linear growth. Here is their model applied to the Lombardy province of Italy:
If the growth of cumulative cases were simply linear, it would follow the dark black dotted line and would have started just before March 16. If it instead followed an exponential curve beginning when it actually began, on February 23, it would follow the blue dotted line. Instead, it followed the red line. The red line traced well along the exponential curve until the lockdown; about ten days after the lockdown, it began tracing well with the linear curve.
Their model replicates in the Veneto province of Italy, the Bayern and Baden states of Germany, South Korea, Singapore, Saudi Arabia, Spain, Germany, and Switzerland.
China is the only exception that seems to have entered a period where no new cases are reported. However, many doubt China's figures, including the CIA.
They explain the trend as follows:
One of the points they make is that to see the true relationship, we need to break the data down to the level of the community in which the cases are freely diffusing. For example, if there is a hotspot in NYC and another in New Orleans and another in Los Angeles, looking at the trend in the United States overall will just muddy up the data.
Data from NYC Are Consistent With the Model
Up-to-date data for NYC can be found here. In the following figures, we must keep in mind that the last seven days are incomplete and should be disregarded. Note also that these are new cases each day, and the graphs in the paper above plotted cumulative cases.
Here are the cases:
The relevant timeline:
CUNY and SUNY shut down on March 11. Restrictions on mass gatherings started on March 12. On March 16, the states of NY, NJ, and CT closed all movie theaters, gyms, and casinos. On March 20, the state closed all “non-essential business.” The new cases should flatten out ten days after these go into place, so we should see it emerge between March 22 and March 30. Data are only complete up to April 5. Although the data are noisy, it's clear the new cases were growing each day through March 20, and they seem to have leveled off by March 27.
Here are the new deaths each day:
The deaths follow a steep upward trend at least until April 5, the last day we can consider the data complete. It's possible they have leveled off since April 5, but it won't be clear if that is true for another few days.
The deaths stick to their rapid increase some 9 to 16 days after the cases level off, reflecting the fact that can it take two weeks from diagnosis to reach critical condition.
The leveling off of the cases is hardly comforting when the deaths have yet to clearly start declining. Anyone working in the context of the NYC crisis is surely wishing the city had acted sooner. Yet the cases only emerged onto our radar some ten days before the strict policies were initiated.
The leveling off of cases to a similar number of new ones each day is consistent with the transition from exponential to linear growth. This suggests that we will see the death toll stay where it is now for at least two weeks, and that we won't start seeing it level off until about two weeks after the new cases start declining.
The Bottom Line
Given that many communities who do not yet have an outbreak on their hands likely have one brewing, that the exponential growth phase in these communities is likely already underway, and that the best protection against a high death toll during the post-social distancing linear phase is to leave the exponential phase as quickly as possible, I believe these data support everyone doing what they can to minimize person-to-person spread even if they have no symptoms and are in communities with no documented outbreaks.
Many people question the importance of this outbreak, and suggest that these are just people dying who would have died anyway from something else. The New York data invalidate this idea.
The last year for which NYC mortality data are complete is 2017. There was an average of 147 deaths per day. There are now over 450 deaths per day due to COVID-19 alone, more than three times the expected total mortality rate.
What is happening in NYC now reflects what happens on the other side of the exponential curve. We exited it and are in the linear phase. We are happy to be exiting the exponential phase, but this linear phase is not a good place to be.
The good news that comes out of this is that we can have a huge impact on the nature of the linear phase by being proactive very early in the exponential phase. Taking this seriously before it seems like a major threat in our backyard is the most powerful choice we can make to keep the burden from becoming overwhelming later on.
Stay safe,
Chris
Several preprints* were released this weekend that, together, suggest three things:
- On the bright side, the social distancing policies are effective at taking us away from the stage of exponential growth.
- On the downside, the transition from exponential growth is not to a period of declining cases and deaths, but to a linear growth of cases and deaths. This linear phase is where the number of new cases and deaths each day remains largely constant, leading to a linear accumulation of total cases and deaths.
- The good news from this is that if social distancing policies are implemented earlier rather than later, the linear phase will have a much lower number of new cases and deaths each day. Since many communities do not have active outbreaks yet, but most will have them soon, many communities can still act to prevent things from getting as bad as they are in places like New York City, where I currently live.
Most Cases Are Undetected
Researchers from Harvard and MIT released a preprint estimating how many cases likely go undetected in the United States using data from Iceland.
The paper used data up through April 2, at which point almost 21,000 Icelanders, about 6% of the population, had been tested.
Iceland has two testing systems:
- One is run by the healthcare system, targeting individuals with severe symptoms or at high risk based on contact with infected individuals or travel to high risk areas.
- The second is run by the company deCODE Genetics and is voluntary and open to anyone not under quarantine and not tested by the healthcare system.
The deCODE testers were not a random sample of the population. In fact, 44% had symptoms of cold and flu, which is much higher than would be expected. As a result, the people who volunteered for testing were probably more likely to have COVID-19.
They dealt with this by performing several analyses, including one that excluded anyone with symptoms. When they did this, they estimated that at least 88.7% of COVID-19 cases go undetected by CDC criteria. When they included the people with cold and flu symptoms, they estimated that 92.5% of COVID-19 cases go undetected by CDC criteria.
These are similar to results published earlier from Wuhan suggesting CDC criteria would miss at least 85% of cases.
Overall these results suggest that only about one in ten cases of COVID-19 get detected in the United States.
Of course, the true rate would require testing in a random sample of the population. Such testing is underway in Iceland, Germany, and Norway.
For now, the one in ten figure makes sense.
Asymptomatics Can Transmit Infection
A researcher from the University of Aukland, New Zealand, released a review of papers documenting asymptomatic transmission.
He identified nine relevant papers. Most of them just document the existence of people who test positive for COVID-19 but do not have symptoms. One woman had lung damage from COVID-19, despite never experiencing symptoms. Several were asymptomatic yet had clusters of infected people in their family. 30-67% of people infected on the Diamond Princess cruise ship were asymptomatic.
These simply show that many people who are infected are asymptomatic. The most compelling case of transmission among those listed seems to be a woman from Shanghai who had no symptoms, but appeared to infect four people at a business meeting in Germany.
Personally, I find it very difficult to believe that asymptomatics cannot spread the infection. The Nature paper showing the virus infects the throatfound that viral loads in the throat were already declining on the first day of symptoms. People should be most infective when they have the highest viral loads in their body fluids. If the highest viral loads of the upper respiratory tract occur prior to the start of symptoms, it seems almost certain that people start spreading it before they have any symptoms.
72% of Counties in the US May Be Undergoing Outbreaks Right Now
A third preprint was released by researchers from the University of Texas at Austin.
These researchers estimated the likelihood that US counties had outbreaks right now that were below the radar of the community.
They made three key assumptions:
- Only one in ten cases are detected (this is supported by the Iceland data I described above.)
- The number of people that can be infected by each person, the reproductive number or R-naught, has declined from 3 to 1.5 as social distancing policies have cut human interactions within the US down by an average of 50%.
- Each county has at least one undetected COVID-19 case.
- If a county has no detected cases, there is a 9% chance an outbreak is underway.
- With a single detected case, there’s a 51% chance an outbreak is underway.
- Overall, 72% of US counties covering 94% of the national population have a more than 50% chance of an outbreak underway.
This suggests that the vast majority of US counties will have outbreaks if they don't have them already, and that many of the outbreaks that are brewing now will not materialize for another few weeks.
Using Ebola Data Suggests a Leveling Off, But Should We Use Ebola Data?
Two researchers from the University of Minnesota released a preprint where they suggested a leveling off was about to occur in the US. They used a statistical model that performed very well in predicting the leveling off of Ebola before it happened, and they assumed we are getting close to the flat top of an S-shaped curve. Here they show that China fits this data and the US is about to:
There are two problems I see with this approach:
- First, Ebola doesn't have anywhere near the transmissibility of COVID-19. As reviewed here, there is no evidence of asymptomatic transmission, and the risk is low with casual contact; human-to-human transmission mainly occurs through direct contact of mucous membranes with the body fluids of the infected person.
- Second, the US data doesn't actually fit the curve yet at all. The top of the S curve is completely imputed from the assumptions. The only example matching the model is China.
Social Distancing Triggers the Transition From Exponential to Linear Growth
The fifth and final of this weekend's preprints I will review here is a paper released from researchers in India.
They suggest a model where the institution of strict social distancing transitions a society from a curve of exponential growth to a curve of linear growth. Here is their model applied to the Lombardy province of Italy:
If the growth of cumulative cases were simply linear, it would follow the dark black dotted line and would have started just before March 16. If it instead followed an exponential curve beginning when it actually began, on February 23, it would follow the blue dotted line. Instead, it followed the red line. The red line traced well along the exponential curve until the lockdown; about ten days after the lockdown, it began tracing well with the linear curve.
Their model replicates in the Veneto province of Italy, the Bayern and Baden states of Germany, South Korea, Singapore, Saudi Arabia, Spain, Germany, and Switzerland.
China is the only exception that seems to have entered a period where no new cases are reported. However, many doubt China's figures, including the CIA.
They explain the trend as follows:
- Initially, the growth is exponential, because the number of people who are infected dictate the number of people who can cause infections in others. If each person can infect several people, then as the number of infected grow, the number of people who can be newly infected each day grows with it. Like compounding interest.
- Since undetected transmission may occur for ten days or so before someone has symptoms, gets tested, and gets a positive result back, social distancing policies take about ten days to initiate their true effects.
- In a perfect quarantine, new cases would slow down and cease. However, any realistic quarantine measures have leaks. These leaks are more likely to happen when there is asymptomatic transmission, because someone can get infected and not realize that they should be taking any measures to protect the people around them. A small leak in the quarantine can allow each infected person to infect one other person. That will lead to a constant rate of new infection. When plotting the cumulative cases over time, it will result in a straight upward line.
One of the points they make is that to see the true relationship, we need to break the data down to the level of the community in which the cases are freely diffusing. For example, if there is a hotspot in NYC and another in New Orleans and another in Los Angeles, looking at the trend in the United States overall will just muddy up the data.
Data from NYC Are Consistent With the Model
Up-to-date data for NYC can be found here. In the following figures, we must keep in mind that the last seven days are incomplete and should be disregarded. Note also that these are new cases each day, and the graphs in the paper above plotted cumulative cases.
Here are the cases:
The relevant timeline:
CUNY and SUNY shut down on March 11. Restrictions on mass gatherings started on March 12. On March 16, the states of NY, NJ, and CT closed all movie theaters, gyms, and casinos. On March 20, the state closed all “non-essential business.” The new cases should flatten out ten days after these go into place, so we should see it emerge between March 22 and March 30. Data are only complete up to April 5. Although the data are noisy, it's clear the new cases were growing each day through March 20, and they seem to have leveled off by March 27.
Here are the new deaths each day:
The deaths follow a steep upward trend at least until April 5, the last day we can consider the data complete. It's possible they have leveled off since April 5, but it won't be clear if that is true for another few days.
The deaths stick to their rapid increase some 9 to 16 days after the cases level off, reflecting the fact that can it take two weeks from diagnosis to reach critical condition.
The leveling off of the cases is hardly comforting when the deaths have yet to clearly start declining. Anyone working in the context of the NYC crisis is surely wishing the city had acted sooner. Yet the cases only emerged onto our radar some ten days before the strict policies were initiated.
The leveling off of cases to a similar number of new ones each day is consistent with the transition from exponential to linear growth. This suggests that we will see the death toll stay where it is now for at least two weeks, and that we won't start seeing it level off until about two weeks after the new cases start declining.
The Bottom Line
Given that many communities who do not yet have an outbreak on their hands likely have one brewing, that the exponential growth phase in these communities is likely already underway, and that the best protection against a high death toll during the post-social distancing linear phase is to leave the exponential phase as quickly as possible, I believe these data support everyone doing what they can to minimize person-to-person spread even if they have no symptoms and are in communities with no documented outbreaks.
Many people question the importance of this outbreak, and suggest that these are just people dying who would have died anyway from something else. The New York data invalidate this idea.
The last year for which NYC mortality data are complete is 2017. There was an average of 147 deaths per day. There are now over 450 deaths per day due to COVID-19 alone, more than three times the expected total mortality rate.
What is happening in NYC now reflects what happens on the other side of the exponential curve. We exited it and are in the linear phase. We are happy to be exiting the exponential phase, but this linear phase is not a good place to be.
The good news that comes out of this is that we can have a huge impact on the nature of the linear phase by being proactive very early in the exponential phase. Taking this seriously before it seems like a major threat in our backyard is the most powerful choice we can make to keep the burden from becoming overwhelming later on.
Stay safe,
Chris
A new preprint* released yesterdaysuggests that ethanol extracts of Scutellaria baicalensis (Chinese Skullcap), or the specific compound found within it known as baicalein, may be effective against COVID-19. However, the way in which baiclaein is metabolized in humans raises some questions that make this herb, in my judgment, unready for prime time.
Please note that I am not a medical doctor and this is not medical advice. I have included a more detailed disclaimer at the bottom. Please note also that neither baicalein nor skullcap have been tested in clinical trials to show they are safe and effective in the specific context of COVID-19.
Chinese Skullcap and the Baicalein Within It Inhibit the Replication of SARS-CoV-2
A crude ethanol extract of Chinese Skullcap inhibited the 3CL protease, also known as the “main protease,” of SARS-CoV-2, the coronavirus that causes COVID-19. The 3CL protease is a key enzyme required for viral replication. It also inhibited the ability of the virus to replicate in vero cells, which are cells used for experiments that are descended from cells taken from African green moneys.
The most effective compound within the extract was baicalein.
A standard metric used to see how much of a particular compound is needed to inhibit an enzyme or the replication of a virus is the concentration required to inhibit either one by 50%, measured as an IC50 or EC50 (IC is for inhibitory concentration, while EC is for effective concentration).
For inhibition of the enzyme, the crude extract had an IC50 of 8.5 micrograms per milliliter (ug/mL), while baicalein had an IC50 of 0.39 micromoles per liter (uM), which is equilvant to 0.01 ug/mL. That makes isolated baicalein about 800 times more powerful than the crude extract.
For inhibition of viral replication, the crude extract had an EC50 of 0.75 ug/mL, while isolated baicalein had an EC50 of 17.6 uM, the equivalent of 0.48 ug/mL. Baicalein is thus only about 1.5 times more powerful than the crude extract when it comes to inhibiting the replication of the virus.
The fact that baicalein was 800 times more effective at inhibiting the main protease but only 1.5 times more effective at inhibiting viral replication suggests that there are other compounds within the extract that have other targets besides the main protease that are useful in inhibiting viral replication.
The isolated baicalein is still a little more powerful than the crude extract, but an extract standardized to provide at least the necessary antiviral dose of baicalein, plus the other unknown components, might be more effective than the dose of baicalein alone, and might be more robust to unforeseen problems since it isn't relying on a single mechanism.
What Dose Would We Need?
How much would we need to consume to have these effects?
Unfortunately, most baicalein is rather quickly metabolized within the human body to baicalin (spelled the same but without the “e”), which has a sugar attached to it. One study found that an 800 milligram (mg) dose of baicalein gave rise to plasma concentrations of 0.029 ug/mL baicalein within 4 hours, while it gave rise to a much higher plasma concentration of 0.396 ug/mL baicalin by 3.5 hours.
Unfortunately the concentrations of baicalein reached are 16 times lower than those needed to slow SARS-CoV-2 growth down by 50% in a test tube.
The only way a safety-tested dose of baicalin could work under these circumstances is if its sugar-bound metabolite is just as effective as it is.
When dosing something continuously, a dose taken every half life will eventually result in a more or less constant concentration in the blood that is roughly double the concentration achieved with a single dose.
The study that looked at the 800 mg dose also looked at 400 mg. 400 mg baicalein led to maximal plasma concentrations of 0.275 ug/mL baicalein within 1 hour, with a halflife of 12 hours. This suggests that 400 mg baicalein taken twice a day 12 hours apart would lead to a roughly steady concentration in the blood of 0.55 ug/mL, which exceeds the concentration required to inhibit half the viral growth in a test tube.
Unfortunately, baicalin might not be anywhere near as effective at inhibiting viral growth as baicalein.
Is Baicalin Less Effective Than Baicalein
This weekend's preprint unfortunately only compared the ability of baicalein and baicalin to inhibit the main protease enzyme and didn't compare their ability to inhibit viral replication.
Baicalin required more than 128 times the concentration of baicalein to inhibit half the enzyme's activity.
It strikes me as a major oversight of the researchers to not also test baicalin's ability to inhibit viral replication. Their results with the crude extract showed that it contained compounds that clearly had other targets than the main protease. The superiority of the baicalein over the crude extract was 800-fold for the enzyme and only 1.5-fold for inhibiting viral replication. Its superiority over baicalin was only 128-fold, so it is certainly possible that it is only slightly superior or not even superior to baicalin for inhibiting viral replication.
The Verdict
I will be keeping my eye on Chinese Skullcap and baicalein as possible additions to my personal regimen as well as my protocol in The Food and Supplement Guide for the Coronavirus, but I will not be adding them at this time and will not be adding them at this time.
My suspicion is that this will only be useful if baicalin turns out to be just as antiviral as baicalein. The results of this weekend's preprint do not support that conclusion, but I hope the authors test it more carefully in the near future by testing the direct ability of baicalin, the sugar-bound metabolite, to inhibit viral replication.
Stay safe,
Chris
Please note that I am not a medical doctor and this is not medical advice. I have included a more detailed disclaimer at the bottom. Please note also that neither baicalein nor skullcap have been tested in clinical trials to show they are safe and effective in the specific context of COVID-19.
Chinese Skullcap and the Baicalein Within It Inhibit the Replication of SARS-CoV-2
A crude ethanol extract of Chinese Skullcap inhibited the 3CL protease, also known as the “main protease,” of SARS-CoV-2, the coronavirus that causes COVID-19. The 3CL protease is a key enzyme required for viral replication. It also inhibited the ability of the virus to replicate in vero cells, which are cells used for experiments that are descended from cells taken from African green moneys.
The most effective compound within the extract was baicalein.
A standard metric used to see how much of a particular compound is needed to inhibit an enzyme or the replication of a virus is the concentration required to inhibit either one by 50%, measured as an IC50 or EC50 (IC is for inhibitory concentration, while EC is for effective concentration).
For inhibition of the enzyme, the crude extract had an IC50 of 8.5 micrograms per milliliter (ug/mL), while baicalein had an IC50 of 0.39 micromoles per liter (uM), which is equilvant to 0.01 ug/mL. That makes isolated baicalein about 800 times more powerful than the crude extract.
For inhibition of viral replication, the crude extract had an EC50 of 0.75 ug/mL, while isolated baicalein had an EC50 of 17.6 uM, the equivalent of 0.48 ug/mL. Baicalein is thus only about 1.5 times more powerful than the crude extract when it comes to inhibiting the replication of the virus.
The fact that baicalein was 800 times more effective at inhibiting the main protease but only 1.5 times more effective at inhibiting viral replication suggests that there are other compounds within the extract that have other targets besides the main protease that are useful in inhibiting viral replication.
The isolated baicalein is still a little more powerful than the crude extract, but an extract standardized to provide at least the necessary antiviral dose of baicalein, plus the other unknown components, might be more effective than the dose of baicalein alone, and might be more robust to unforeseen problems since it isn't relying on a single mechanism.
What Dose Would We Need?
How much would we need to consume to have these effects?
Unfortunately, most baicalein is rather quickly metabolized within the human body to baicalin (spelled the same but without the “e”), which has a sugar attached to it. One study found that an 800 milligram (mg) dose of baicalein gave rise to plasma concentrations of 0.029 ug/mL baicalein within 4 hours, while it gave rise to a much higher plasma concentration of 0.396 ug/mL baicalin by 3.5 hours.
Unfortunately the concentrations of baicalein reached are 16 times lower than those needed to slow SARS-CoV-2 growth down by 50% in a test tube.
The only way a safety-tested dose of baicalin could work under these circumstances is if its sugar-bound metabolite is just as effective as it is.
When dosing something continuously, a dose taken every half life will eventually result in a more or less constant concentration in the blood that is roughly double the concentration achieved with a single dose.
The study that looked at the 800 mg dose also looked at 400 mg. 400 mg baicalein led to maximal plasma concentrations of 0.275 ug/mL baicalein within 1 hour, with a halflife of 12 hours. This suggests that 400 mg baicalein taken twice a day 12 hours apart would lead to a roughly steady concentration in the blood of 0.55 ug/mL, which exceeds the concentration required to inhibit half the viral growth in a test tube.
Unfortunately, baicalin might not be anywhere near as effective at inhibiting viral growth as baicalein.
Is Baicalin Less Effective Than Baicalein
This weekend's preprint unfortunately only compared the ability of baicalein and baicalin to inhibit the main protease enzyme and didn't compare their ability to inhibit viral replication.
Baicalin required more than 128 times the concentration of baicalein to inhibit half the enzyme's activity.
It strikes me as a major oversight of the researchers to not also test baicalin's ability to inhibit viral replication. Their results with the crude extract showed that it contained compounds that clearly had other targets than the main protease. The superiority of the baicalein over the crude extract was 800-fold for the enzyme and only 1.5-fold for inhibiting viral replication. Its superiority over baicalin was only 128-fold, so it is certainly possible that it is only slightly superior or not even superior to baicalin for inhibiting viral replication.
The Verdict
I will be keeping my eye on Chinese Skullcap and baicalein as possible additions to my personal regimen as well as my protocol in The Food and Supplement Guide for the Coronavirus, but I will not be adding them at this time and will not be adding them at this time.
My suspicion is that this will only be useful if baicalin turns out to be just as antiviral as baicalein. The results of this weekend's preprint do not support that conclusion, but I hope the authors test it more carefully in the near future by testing the direct ability of baicalin, the sugar-bound metabolite, to inhibit viral replication.
Stay safe,
Chris
Two preprints* were released yesterday that add to the growing evidence that hydroxychloroquine is not useful in COVID-19, contrary to all the hype.
Please note that I am not a medical doctor and this is not medical advice. A more detailed disclaimer can be found at the bottom of the page.
Let's take a look at the data.
A Second RCT Confirms No Effect of Hydroxychloroquine
The first randomized controlled trial (RCT) of hydroxychloroquine was published in Chinese. I used Google Translate to read it, and analyzed it here. It was a small study done in 30 patients and found no effect of 400 mg hydroxychloroquine once a day for five days on clearance of the virus after seven days or two weeks.
A preprint of a new RCT was released yesterday. It was larger and used higher doses.
This new trial used 1200 mg a day for three days followed by 800 mg a day for a total treatment time of two weeks for mild and moderate cases and three weeks for severe cases.
They originally designed the study to include 360 patients, but were only able to admit 191. Of those, 41 were excluded for reasons such as allergies to hydroxychloroquine or chloroquine, liver or kidney diseases that hurt the metabolism and elimination of hydroxychloroquine, cognitive and mental deficits, and women who were pregnant or nursing. That left 150 patients who were randomly allocated, 75 to a group that received only the standard of care, 75 to a group that received the standard of care plus hydroxychloroquine.
Patients were randomized an average of 17 days after they had first gotten sick, although 33 of them (22%) were randomized less than seven days after getting sick.
Their primary endpoint was clearance of the virus.
Their secondary endpoints included a composite score for resolving “symptoms,” which included resolving fever, normalizing the oxygen content of the capillary blood, and recovering from respiratory symptoms (nasal congestion, cough, sore throat, phlegm, and shortness of breath). Another secondary endpoint included normalization of lab markers of inflammation, such as C-reactive protein (CRP), the erythrocyte sedimentation rate, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha).
No Effect on Viral Clearance or Symptom Alleviation
Hydroxychloroquine had no effect on the clearance of the virus at any time point, including 4, 7, 10, 14, 21, or 28 days after randomization.
Their BMI, preexisting conditions, baseline inflammatory markers, use of other drugs, and whether they were randomized before or after 7 days of being sick all had no effect on the results.
Hydroxychloroquine had no effect on whether their symptoms were alleviated by the end of the trial, or the average time it took to reach symptom alleviation.
Fishing for Significance
The authors did claim that symptoms were alleviated faster anyway on the basis that symptom relief was higher in the hydroxychloroquine group than in the control group during the second week. However, this was not very impressive and it was not statistically significant. It is almost fully explained as follows: roughly 15% of people achieved symptom alleviation on day 9 with hydroxychloroquine, while their counterparts in the control group caught up on day 10; another 10% in the hydroxychloroquine group achieved symptom alleviation on day 11, while their counterparts in the control group caught up on day 14.
Since this was not statistically significant, the authors performed a subgroup analysis on it. Along with 13 other comparisons, they looked at the 28 people (19%) who were not taking other drugs that had potential antiviral activity. In this small subgroup, 8 people in the hydroxychloroquine group reached symptom alleviation in the second week while only one did in the control group. This was statistically significant at just a sliver under P=0.05.
The relevance of this subgroup analysis is doubtful. As the authors noted, none of the drugs they considered potentially antiviral (such as lopinavir-ritonavir, arbidol, oseltamivir, virazole, entecavir, ganciclovir and/or interferon-alpha) have any evidence yet for their efficacy in the context of COVID-19, and lopinavir-ritonavir already has an RCT showing it is not effective.
More to the point, the authors made 14 subgroup comparisons for symptom alleviation in the second week and the same 14 subgroup comparisons for viral clearance. That's 28 comparisons, one reaching statistical significance. Statistical significance at p<0.05 by definition means that if there were no effect at all, you would expect one out of 20 tests to reach significance just on random chance alone.
That is exactly what the authors found.
Although these results are perfectly consistent with complete random chance and no effect at all of the drug, they claimed that “adding hydroxychloroquine to the current standard-of-care in patients with COVID-19 does not increase virus response but accelerate the alleviation of clinical symptoms.” This conclusion is dubious and contradicts their own pre-planned analysis of symptom alleviation as a secondary endpoint.
An Effect on Inflammation?
The authors didn't examine the erythrocyte sedimentation rate, IL-6, or TNF-alpha as planned because these measurements were not available for a large enough number of patients.
However, they did have data for CRP and the lymphocyte count.
Severe COVID-19 cases are associated with elevated CRP, often above 40 mg/L, and low lymphocyte counts. As I noted in the elderberry post, low lymphocyte counts in COVID-19 are a major predictor of severity and death.
CRP declined by 7 mg/L in the hydroxychloroquine group and 2.7 mg/L in the control group. The difference in the decrease was statistically significant at P=0.045.
The absolute lymphocyte count increased 62 per microliter in the hydroxychloroquine group and 8 per microliter in the control group. With normal lymphocyte counts between 1000 and 4800 per microliter, these seem meaningless. The P value was 0.547, meaning there would be a 55% chance of observing this difference if there were no effect of the drug.
Unfortunately, the authors do not report the absolute concentrations of CRP or lymphocytes. They only report the change from baseline.
Whenever I see a paper that only reports change from baseline, I assume the authors are hiding behind bad data and trying to cover up a statistical artifact like regression to the mean. Regression to the mean is the tendency for a randomly high value to come down, and a randomly low value to go up. If the baseline CRP in the hydroxychloroquine group was 50 and was 45 in the control group, then a 7-point decline in the hydroxychloroquine group and a 3-point decline in the control group would bring both groups to 43, an identical level. You would expect something like that from regression to the mean.
I wrote a post explaining this nine years ago, How a Study Can Show Something to Be True When It’s Completely False — Regression to the Mean.
The appropriate analysis for CRP would have been to show that the concentration of CRP at the end of the trial was lower in one group than the other. They did not report that data, so the finding should be disregarded.
They claimed that their study showed that “adding hydroxychloroquine to the current standard-of-care in patients with COVID-19 does not increase virus response but accelerate the alleviation of clinical symptoms, possibly through anti-inflammatory properties and recovery of lymphopenia,” but they didn't show acceleration of the alleviation of clinical symptoms or improvements in CRP (inflammatory properties) or lymphocyte counts (lymphopenia).
Since hydroxychloroquine is an immunosupressant used to treat lupus and rheumatoid arthritis, it wouldn't be terribly surprising if it were able to calm CRP, recover the lymphocytes, and perhaps protect against the cytokine storm that leads to severe respiratory problems and death. In addition to the lack of compelling data in this study, however, the second preprint released yesterday casts further doubt on this hypothesis.
The Second Study: No Effect in Severe Cases
The second preprint released yesterday was appropriately titled, No evidence of clinical efficacy of hydroxychloroquine in patients hospitalized for COVID-19 infection with oxygen requirement.”
This was not a randomized controlled trial. Instead, they collected data from routine care to “emulate” a trial.
All electronic health records from March 17-31 of patients in four French medical centers used for COVID-19 pneumonia were searched for patients between the ages of 18-80 who had PCR-confirmed COVID-19 and required supplemental oxygen.
They excluded any patients under dialysis or with any other contraindication for hydroxychloroquine, anyone using hydroxychloroquine prior to admission, anyone treated with another experimental COVID-19 drug within 48 hours of admission, and anyone with organ failure or acute respiratory distress syndrome (ARDS) at admission. Patients were also excluded if they had been discharge from ICU to standard care or if at admission they had made the decision to not get treated at admission or expressed opposition to their data being collected.
They compared patients who received hydroxychloroquine at 600 mg per day starting within the first 48 h after admission to those who did not receive any of the drug, over the course of seven days.
Their primary outcome was the number of people who were either transferred to ICU or died from any cause within 7 days.
Of 181 eligible patients, 84 had received hydroxychloroquine within 48 hours of admission and 97 did not.
In the primary endpoint, 20.5% of those using hydroxychloroquine and 22.1% of those in the control group transferred to ICU or died.
3 patients in the hydroxychloroquine-treated group and 4 in the control group died.
In addition, 27.7% of the hydroxychloroquine-treated patients and 24.1% of the controls developed ARDS.
The numbers of deaths are too small to be meaningful. The percentages in the ICU/died and ARDS comparisons are almost identical (ARDS looks slightly better for the controls, while ICU/died looks slightly better for hydroxychloroquine) and not statistically significant.
The title phrase “no evidence of clinical efficacy of hydroxychloroquine” was appropriate.
Since inflammation plays a major role in the progression of severe cases to ARDS, critical care, and death, this study suggests that the immunosuppressive activity of hydroxychloroquine is unlikely to be of benefit in suppressing the COVID-19 cytokine storm.
Side Effects and Safety
In the RCT, 21% (30 patients) in the hydroxychloroquine group and only 8.8% (7 patients) in the control group reported adverse effects. The most common adverse effect was diarrhea. Two patients in the hydroxychloroquine group and zero controls progressed to severe COVID-19 symptoms. The drug was discontinued in one patient due to blurred vision, and the dose was adjusted downward in another patient who reported thirst as an adverse effect.
In the non-randomized French study, 9.5% of patients taking hydroxychloroquine develoepd abnormalities in their heart rhythm that required them to be taken off the medication according to French national guidelines. One developed atrioventricular block and one developed left bundle branch block, both of which are impairments in the ability of electrical signals to travel through the heart and keep it beating properly.
When comparing the safety profile in the two studies, the side effects seem to be more concerning in people with severe COVID-19. This further questions the possibility that the immunosuppressive properties of hydroxychloroquine could be used to counter the dangerous inflammation of the cytokine storm in severe cases.
Hydroxychloroquine in Context
Three other issues of this newsletter have been devoted to chloroquine and hydroxychloroquine:
Hydroxychloroquine's immunosuppressive properties make it useful for inflammatory disorders such as lupus and rheumatoid arthritis.
Chloroquine, however, has a terrible track record for antiviral properties. In vitro, meaning in a test tube, it is antiviral toward the flu, dengue, and chikungunya. But it has failed to prove beneficial in humans for the flu and dengue, and it acted as a proviral in multiple animal models for chikungunya.
These drugs are cellular poisons with both antiviral and immunosuppressive properties. In COVID-19, which will win out?
So far it looks like neither. Perhaps it's putting patients in a tug-of-war that is being pulled equally from both ends.
As data comes in, particularly RCTs, it looks more and more like the drug does very little if anything.
Stay safe,
Chris
Please note that I am not a medical doctor and this is not medical advice. A more detailed disclaimer can be found at the bottom of the page.
Let's take a look at the data.
A Second RCT Confirms No Effect of Hydroxychloroquine
The first randomized controlled trial (RCT) of hydroxychloroquine was published in Chinese. I used Google Translate to read it, and analyzed it here. It was a small study done in 30 patients and found no effect of 400 mg hydroxychloroquine once a day for five days on clearance of the virus after seven days or two weeks.
A preprint of a new RCT was released yesterday. It was larger and used higher doses.
This new trial used 1200 mg a day for three days followed by 800 mg a day for a total treatment time of two weeks for mild and moderate cases and three weeks for severe cases.
They originally designed the study to include 360 patients, but were only able to admit 191. Of those, 41 were excluded for reasons such as allergies to hydroxychloroquine or chloroquine, liver or kidney diseases that hurt the metabolism and elimination of hydroxychloroquine, cognitive and mental deficits, and women who were pregnant or nursing. That left 150 patients who were randomly allocated, 75 to a group that received only the standard of care, 75 to a group that received the standard of care plus hydroxychloroquine.
Patients were randomized an average of 17 days after they had first gotten sick, although 33 of them (22%) were randomized less than seven days after getting sick.
Their primary endpoint was clearance of the virus.
Their secondary endpoints included a composite score for resolving “symptoms,” which included resolving fever, normalizing the oxygen content of the capillary blood, and recovering from respiratory symptoms (nasal congestion, cough, sore throat, phlegm, and shortness of breath). Another secondary endpoint included normalization of lab markers of inflammation, such as C-reactive protein (CRP), the erythrocyte sedimentation rate, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha).
No Effect on Viral Clearance or Symptom Alleviation
Hydroxychloroquine had no effect on the clearance of the virus at any time point, including 4, 7, 10, 14, 21, or 28 days after randomization.
Their BMI, preexisting conditions, baseline inflammatory markers, use of other drugs, and whether they were randomized before or after 7 days of being sick all had no effect on the results.
Hydroxychloroquine had no effect on whether their symptoms were alleviated by the end of the trial, or the average time it took to reach symptom alleviation.
Fishing for Significance
The authors did claim that symptoms were alleviated faster anyway on the basis that symptom relief was higher in the hydroxychloroquine group than in the control group during the second week. However, this was not very impressive and it was not statistically significant. It is almost fully explained as follows: roughly 15% of people achieved symptom alleviation on day 9 with hydroxychloroquine, while their counterparts in the control group caught up on day 10; another 10% in the hydroxychloroquine group achieved symptom alleviation on day 11, while their counterparts in the control group caught up on day 14.
Since this was not statistically significant, the authors performed a subgroup analysis on it. Along with 13 other comparisons, they looked at the 28 people (19%) who were not taking other drugs that had potential antiviral activity. In this small subgroup, 8 people in the hydroxychloroquine group reached symptom alleviation in the second week while only one did in the control group. This was statistically significant at just a sliver under P=0.05.
The relevance of this subgroup analysis is doubtful. As the authors noted, none of the drugs they considered potentially antiviral (such as lopinavir-ritonavir, arbidol, oseltamivir, virazole, entecavir, ganciclovir and/or interferon-alpha) have any evidence yet for their efficacy in the context of COVID-19, and lopinavir-ritonavir already has an RCT showing it is not effective.
More to the point, the authors made 14 subgroup comparisons for symptom alleviation in the second week and the same 14 subgroup comparisons for viral clearance. That's 28 comparisons, one reaching statistical significance. Statistical significance at p<0.05 by definition means that if there were no effect at all, you would expect one out of 20 tests to reach significance just on random chance alone.
That is exactly what the authors found.
Although these results are perfectly consistent with complete random chance and no effect at all of the drug, they claimed that “adding hydroxychloroquine to the current standard-of-care in patients with COVID-19 does not increase virus response but accelerate
An Effect on Inflammation?
The authors didn't examine the erythrocyte sedimentation rate, IL-6, or TNF-alpha as planned because these measurements were not available for a large enough number of patients.
However, they did have data for CRP and the lymphocyte count.
Severe COVID-19 cases are associated with elevated CRP, often above 40 mg/L, and low lymphocyte counts. As I noted in the elderberry post, low lymphocyte counts in COVID-19 are a major predictor of severity and death.
CRP declined by 7 mg/L in the hydroxychloroquine group and 2.7 mg/L in the control group. The difference in the decrease was statistically significant at P=0.045.
The absolute lymphocyte count increased 62 per microliter in the hydroxychloroquine group and 8 per microliter in the control group. With normal lymphocyte counts between 1000 and 4800 per microliter, these seem meaningless. The P value was 0.547, meaning there would be a 55% chance of observing this difference if there were no effect of the drug.
Unfortunately, the authors do not report the absolute concentrations of CRP or lymphocytes. They only report the change from baseline.
Whenever I see a paper that only reports change from baseline, I assume the authors are hiding behind bad data and trying to cover up a statistical artifact like regression to the mean. Regression to the mean is the tendency for a randomly high value to come down, and a randomly low value to go up. If the baseline CRP in the hydroxychloroquine group was 50 and was 45 in the control group, then a 7-point decline in the hydroxychloroquine group and a 3-point decline in the control group would bring both groups to 43, an identical level. You would expect something like that from regression to the mean.
I wrote a post explaining this nine years ago, How a Study Can Show Something to Be True When It’s Completely False — Regression to the Mean.
The appropriate analysis for CRP would have been to show that the concentration of CRP at the end of the trial was lower in one group than the other. They did not report that data, so the finding should be disregarded.
They claimed that their study showed that “adding hydroxychloroquine to the current standard-of-care in patients with COVID-19 does not increase virus response but accelerate
Since hydroxychloroquine is an immunosupressant used to treat lupus and rheumatoid arthritis, it wouldn't be terribly surprising if it were able to calm CRP, recover the lymphocytes, and perhaps protect against the cytokine storm that leads to severe respiratory problems and death. In addition to the lack of compelling data in this study, however, the second preprint released yesterday casts further doubt on this hypothesis.
The Second Study: No Effect in Severe Cases
The second preprint released yesterday was appropriately titled, No evidence of clinical efficacy of hydroxychloroquine in patients hospitalized for COVID-19 infection with oxygen requirement.”
This was not a randomized controlled trial. Instead, they collected data from routine care to “emulate” a trial.
All electronic health records from March 17-31 of patients in four French medical centers used for COVID-19 pneumonia were searched for patients between the ages of 18-80 who had PCR-confirmed COVID-19 and required supplemental oxygen.
They excluded any patients under dialysis or with any other contraindication for hydroxychloroquine, anyone using hydroxychloroquine prior to admission, anyone treated with another experimental COVID-19 drug within 48 hours of admission, and anyone with organ failure or acute respiratory distress syndrome (ARDS) at admission. Patients were also excluded if they had been discharge from ICU to standard care or if at admission they had made the decision to not get treated at admission or expressed opposition to their data being collected.
They compared patients who received hydroxychloroquine at 600 mg per day starting within the first 48 h after admission to those who did not receive any of the drug, over the course of seven days.
Their primary outcome was the number of people who were either transferred to ICU or died from any cause within 7 days.
Of 181 eligible patients, 84 had received hydroxychloroquine within 48 hours of admission and 97 did not.
In the primary endpoint, 20.5% of those using hydroxychloroquine and 22.1% of those in the control group transferred to ICU or died.
3 patients in the hydroxychloroquine-treated group and 4 in the control group died.
In addition, 27.7% of the hydroxychloroquine-treated patients and 24.1% of the controls developed ARDS.
The numbers of deaths are too small to be meaningful. The percentages in the ICU/died and ARDS comparisons are almost identical (ARDS looks slightly better for the controls, while ICU/died looks slightly better for hydroxychloroquine) and not statistically significant.
The title phrase “no evidence of clinical efficacy of hydroxychloroquine” was appropriate.
Since inflammation plays a major role in the progression of severe cases to ARDS, critical care, and death, this study suggests that the immunosuppressive activity of hydroxychloroquine is unlikely to be of benefit in suppressing the COVID-19 cytokine storm.
Side Effects and Safety
In the RCT, 21% (30 patients) in the hydroxychloroquine group and only 8.8% (7 patients) in the control group reported adverse effects. The most common adverse effect was diarrhea. Two patients in the hydroxychloroquine group and zero controls progressed to severe COVID-19 symptoms. The drug was discontinued in one patient due to blurred vision, and the dose was adjusted downward in another patient who reported thirst as an adverse effect.
In the non-randomized French study, 9.5% of patients taking hydroxychloroquine develoepd abnormalities in their heart rhythm that required them to be taken off the medication according to French national guidelines. One developed atrioventricular block and one developed left bundle branch block, both of which are impairments in the ability of electrical signals to travel through the heart and keep it beating properly.
When comparing the safety profile in the two studies, the side effects seem to be more concerning in people with severe COVID-19. This further questions the possibility that the immunosuppressive properties of hydroxychloroquine could be used to counter the dangerous inflammation of the cytokine storm in severe cases.
Hydroxychloroquine in Context
Three other issues of this newsletter have been devoted to chloroquine and hydroxychloroquine:
- A French Trial Suggests Hydroxychloroquine is Promising Yet Risky, but Wasn’t Randomized
- Can Hydroxychloroquine or Chloroquine Treat COVID-19?
- Are Chloroquine and Hydroxychloroquine Zinc Ionophores?
Hydroxychloroquine's immunosuppressive properties make it useful for inflammatory disorders such as lupus and rheumatoid arthritis.
Chloroquine, however, has a terrible track record for antiviral properties. In vitro, meaning in a test tube, it is antiviral toward the flu, dengue, and chikungunya. But it has failed to prove beneficial in humans for the flu and dengue, and it acted as a proviral in multiple animal models for chikungunya.
These drugs are cellular poisons with both antiviral and immunosuppressive properties. In COVID-19, which will win out?
So far it looks like neither. Perhaps it's putting patients in a tug-of-war that is being pulled equally from both ends.
As data comes in, particularly RCTs, it looks more and more like the drug does very little if anything.
Stay safe,
Chris
In the coronavirus discussion thread within the Vitamins and Minerals 101 Premium group, one of the members asked me to look into the possibility that the anti-parasitic drug, ivermectin, could treat COVID-19.
Please note that I have a PhD in Nutritional Sciences, I am not a medical doctor, and this is not medical advice.
That ivermectin might be helpful was suggested by a study done in vitro, meaning in a lab dish. This studyexamined the ability of ivermectin to reduce the replication of SARS-CoV-2, the coronavirus that causes COVID-19, in isolated cells. They found that 5 micromoles per liter (uM, a measure of the number of molecules per liter) of ivermectin caused a 5000-fold reduction in the amount of virus within 48 hours, effectively completely clearing it. The concentration that eliminated half the viral RNA, known as the IC50, was between 2.2 and 2.5 uM. The minimal concentration required to have any antiviral activity at all was somewhere between 1 and 2 uM.
A new preprint* released today casts serious doubt that this in vitro study has any relevance at all.
These authors collected all the literature on ivermectin dosing that reported the blood concentrations reached with the drug.
The established doses of the drug used for various parasitic infections range from 150 to 400 micrograms per kilogram bodyweight (ug/kg), usually administered once per year, and there are also reports of the blood concentrations reached by excessive doses up to 2000 ug/kg.
The highest blood concentration reported in the literature for this drug is 283.2 nanomoles per liter (nM), from the unnecessarily high dose of 2000 ug/kg. One nanomole is a thousandth of a micromole, so this is equivalent to 0.28 uM. This is 17 times lower than the concentration required to eliminate the virus over 48 hours, 8 times lower than the concentration required to achieve 50% reduction in the virus, and somewhere between 3.5 and 7 times lower than the concentration to have any antiviral activity at all.
It took 48 hours of sustaining these concentrations to produce the antiviral effects reported in isolated cells in the first paper. But the half-life of the drug at the highest dose tested was 4.2 hours. That means the drug would be gone after one day, and the peak concentration would only be sustained for a short period of time, not for 48 hours.
The ivermectin doses are used once a year, and sometimes once every three months. To sustain a concentration in the blood over time, the drug has to be dosed repeatedly. For example, dosing the drug once every half life will sustain a concentration roughly double of the peak concentration reached after a single dose. 2000 ug/kg (120 mg for the average person) every 4 hours would be expected to eventually produce a steady concentration of about 0.58 uM, still well under the concentration needed to be effective. Sustaining the concentrations required to eliminate the virus for 48 hours would likely require 5-10 times this.
Such doses are probably wildly unsafe. The drug is never used at anywhere near those doses therapeutically, and the literature includes an overdose at 200 milligrams, which is about 67% greater than the highest dose for which we know the peak blood concentrations. This was a 46-year-old man who developed drowsiness, unconsciousness, weakness, inability to control his movements, and visual changes. Achieving antiviral activity against SARS-CoV-2 would probably have required him to take 3-6 times this dose every four hours for two days, at which point the toxicity could have been far worse and perhaps lethal.
At the present time, ivermectin should not be considered a safe way to prevent or treat COVID-19.
Stay safe,
Chris
Please note that I have a PhD in Nutritional Sciences, I am not a medical doctor, and this is not medical advice.
That ivermectin might be helpful was suggested by a study done in vitro, meaning in a lab dish. This studyexamined the ability of ivermectin to reduce the replication of SARS-CoV-2, the coronavirus that causes COVID-19, in isolated cells. They found that 5 micromoles per liter (uM, a measure of the number of molecules per liter) of ivermectin caused a 5000-fold reduction in the amount of virus within 48 hours, effectively completely clearing it. The concentration that eliminated half the viral RNA, known as the IC50, was between 2.2 and 2.5 uM. The minimal concentration required to have any antiviral activity at all was somewhere between 1 and 2 uM.
A new preprint* released today casts serious doubt that this in vitro study has any relevance at all.
These authors collected all the literature on ivermectin dosing that reported the blood concentrations reached with the drug.
The established doses of the drug used for various parasitic infections range from 150 to 400 micrograms per kilogram bodyweight (ug/kg), usually administered once per year, and there are also reports of the blood concentrations reached by excessive doses up to 2000 ug/kg.
The highest blood concentration reported in the literature for this drug is 283.2 nanomoles per liter (nM), from the unnecessarily high dose of 2000 ug/kg. One nanomole is a thousandth of a micromole, so this is equivalent to 0.28 uM. This is 17 times lower than the concentration required to eliminate the virus over 48 hours, 8 times lower than the concentration required to achieve 50% reduction in the virus, and somewhere between 3.5 and 7 times lower than the concentration to have any antiviral activity at all.
It took 48 hours of sustaining these concentrations to produce the antiviral effects reported in isolated cells in the first paper. But the half-life of the drug at the highest dose tested was 4.2 hours. That means the drug would be gone after one day, and the peak concentration would only be sustained for a short period of time, not for 48 hours.
The ivermectin doses are used once a year, and sometimes once every three months. To sustain a concentration in the blood over time, the drug has to be dosed repeatedly. For example, dosing the drug once every half life will sustain a concentration roughly double of the peak concentration reached after a single dose. 2000 ug/kg (120 mg for the average person) every 4 hours would be expected to eventually produce a steady concentration of about 0.58 uM, still well under the concentration needed to be effective. Sustaining the concentrations required to eliminate the virus for 48 hours would likely require 5-10 times this.
Such doses are probably wildly unsafe. The drug is never used at anywhere near those doses therapeutically, and the literature includes an overdose at 200 milligrams, which is about 67% greater than the highest dose for which we know the peak blood concentrations. This was a 46-year-old man who developed drowsiness, unconsciousness, weakness, inability to control his movements, and visual changes. Achieving antiviral activity against SARS-CoV-2 would probably have required him to take 3-6 times this dose every four hours for two days, at which point the toxicity could have been far worse and perhaps lethal.
At the present time, ivermectin should not be considered a safe way to prevent or treat COVID-19.
Stay safe,
Chris
EMF Mitigation - Flush Niacin - Big 5 Minerals
