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Thread: Disease and pandemics thread (because it's science)

  1. #1471
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    The Atlantic magazine has a good article about the current thinking on masks, at https://www.theatlantic.com/health/a...-masks/609235/. Here is a relevant quote:
    In the U.S., the CDC is reportedly contemplating a change in guidance, and many public-health experts have already pivoted. “I went with the public-health message at the beginning: People don’t need masks,” Marr said. “But I’ve changed because of the mounting evidence that it does seem to be spreading through the air.”
    Other doctors are not so sure. But I see obvious logical problems in statements like:
    "Other studies have been more equivocal, finding that masks provide no benefit, small benefits, or benefits only in conjunction with measures like hand-washing."
    The problem in the logic here is taking that statement, and interpreting "masks won't always work, and sometimes might not work at all" as meaning "so you shouldn't wear masks." And how about saying masks don't work well unless combined with handwashing? Just combine them with handwashing, for crying out loud.

    And the other thing is that there is not enough attention on the difference between masks protecting the wearer, versus protecting everyone else. I've even heard it said that the only people who should wear masks are those who are sick, which is obvious nonsense because many people won't know they are sick, or won't self identify as sick even when symptoms first begin. If we think a mask is protective of the public when worn by sick people, and we agree that sensible policy is to regard everyone as sick at all times when we make simple low-impact decisions like whether to get into an elevator with them or not, then obviously everyone should wear masks at all times in public. The issue of availability is not a reason to change that, it's a reason to be more intelligent about availability. (Make more, make a range of protection levels, use responsibly, don't hoard, etc.-- none of those say "don't wear masks.")
    Last edited by Ken G; 2020-Apr-03 at 05:16 PM.

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    News from the public briefing in the UK today is that the literature review carried out for the WHO (led by an academic in Hong Kong, interestingly) has concluded there is still no evidence that public mask wearing has any impact on the progress of an epidemic. I haven't found an official statement from the WHO yet, but I have no reason to doubt the reported conversation with the review chair.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Have you ever coughed or sneezed while wearing a surgical mask?
    yes

    Quote Originally Posted by grant hutchison View Post
    News from the public briefing in the UK today is that the literature review carried out for the WHO (led by an academic in Hong Kong, interestingly) has concluded there is still no evidence that public mask wearing has any impact on the progress of an epidemic. I haven't found an official statement from the WHO yet, but I have no reason to doubt the reported conversation with the review chair. Grant Hutchison
    I wonder if having the virus settled on the outside of the mask would lead to it being inhaled through the mask fibers when the mask wearer breathes in. Or the mask wearer touches/adjusts the mask by touching the outside, automatically infecting himself by picking up viruses on the outer surface.
    Do good work. —Virgil Ivan "Gus" Grissom

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    Quote Originally Posted by Van Rijn View Post
    I watched one interview with Oz some days ago about this. My impression was that he was cheerleading for the drug, but after talking it up he put in some qualifiers. I don’t care for that behavior. Like I mentioned in my last post, other doctors consider existing “studies” to be junk (or worse), but he didn’t say anything like that.
    I would agree if there were some real alternative drugs, or are there? I agree that Oz is cheerleading to help place emphasis on HCQ in order to get real trials conducted. In the interim what do doctors do, not prescribe it if it does offer a glimmer of help to a patient who could die from the disease?

    It was reported on the news that a survey (Sermo Survey) of 6,227 doctors that 37% of them favored it as a treatment. One could easily argue that 63% don't favor it and "that would be that" in most cases. But given the lack of therapeutics, any indicator that it may prove effective or even somewhat effective is worth looking at and not casually in the case of a pandemic.

    Also from the news, in Spain, 72% of the cases are receiving HCQ. But given Spain's high numbers, my first thought was that it might even be used as a disqualifier instead. So, I have included it in a plot that I will post shortly that does show significant, or perhaps somewhat significant, recent improvements. Can we attribute those improvements to HCQ? I don't know, but a maybe at this point is worth considering. Yes?

    Of course it can be tested, and should be, but in my opinion at this point the position should be that this is one of a number of drugs that is to be tested in proper studies, and until that’s done we can’t say much about it. Also the problems with current “studies” should be pointed out. And that’s it. It shouldn’t be promoted or put ahead of other investigational drugs.
    I hope there are other and more preferred drugs warranting greater efforts in trials. Are you aware of which those might be? If there are other drugs holding greater promise, why don't we hear about them? I think hope is too important to not allow all drugs that show any promise to be mentioned. My wife (in her 60s, diabetic, overweight, Type A blood) is convinced she will die if she gets the disease. HCQ is a way to stimulate some hope for her, and everyone, knowing our medical professionals will offer her greater assurances with time, so HCQ might be a reasonable stepping stone of hope to get us through the present when the promise isn't now but the future. She (and I as well, of course) will be more than delighted, however, to hear of a better and safer drug that may be in use now.


    Again, here is an article I linked to in my earlier post on this, discussing hydroxychloroquine and azithromycin and some of the bad science surrounding it:

    https://sciencebasedmedicine.org/are...-for-covid-19/

    There is a follow-up:

    https://sciencebasedmedicine.org/hyd...rsus-covid-19/

    It discusses another “study” that Raoult has put forward, how poor it is, yet Oz is apparently promoting it.
    Okay, weaknesses and possible fallacies of any "scientific" report need to be emphasized and those seem to be fair statements.

    But in spite of all his rancor, he, near the end stated, "So, could hydroxychloroquine and chloroquine be effective drugs to treat and/or prevent COVID-19? Sure, it’s possible. There’s a plausible mechanism by which the drugs could inhibit viral replication (several, actually), plus in vitro evidence of antiviral activity." [my bold]

    If the possibility exists that HCQ might "prove" effective at some point, will he regret stating, "Overall, Raoult strikes me as a “brave maverick” who might have been a great scientist in his prime but who has now become arrogant and dictatorial and has now come down with a serious case of the Dunning-Kruger effect."? Probably not.

    I trust him a lot more than Oz. He often covers questionable medical claims with a skeptical focus.
    Trust to scrutinize medical reports/papers, okay. Trust to offer hope for a potential therapeutic during a pandemic, what does he offer?

    Not everyone that can write prescriptions has the expertise to properly evaluate this and has done so. Hopefully the majority are skeptical and considering risks, but there are credulous doctors too that can be taken in by hype. There are doctors that are just plain bad. As I mentioned before, there are dentists that have tried to write prescriptions for this. It doesn’t take a huge number of doctors to cause shortages for a drug like this that is being produced for established uses with an expected level of demand.
    Agreed.

    The AMA site presents very little on this, though I had hoped they would weigh-in with a thorough review. Perhaps associations don't do such things. Regardless I was a bit disappointed with what I found there.

    Quote Originally Posted by AMA
    We are issuing this joint statement to highlight the important role that physicians, pharmacists and health systems play in being just stewards of health care resources during times of emergency and national disaster. We are aware that some physicians and others are prophylactically prescribing medications currently identified as potential treatments for COVID-19 (e.g., chloroquine or hydroxychloroquine, azithromycin) for themselves, their families, or their colleagues; and that some pharmacies and hospitals have been purchasing excessive amounts of these medications in anticipation of potentially using them for COVID-19 prevention and treatment. We strongly oppose these actions.

    We collectively support state and federal requirements that direct a prescription must be written only for a legitimate medical purpose.
    I think they should better define what they mean by legitimate since aren't prescribing drugs that may inhibit a contagion a medical purpose? Until supplies are better addressed, prescriptions limitations should be better defined and updated with improved knowledge of effectiveness, which may be earlier and not just prior to intubation, perhaps, though, I am just an Average Joe after all. So I'm more about learning than preaching, so apply salt where needed.
    We know time flies, we just can't see its wings.

  5. #1475
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    Here is an update as of yesterday's Johns Hopkins data...

    Attachment 25074
    We know time flies, we just can't see its wings.

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    Quote Originally Posted by grant hutchison View Post
    Well, I got the idea from the large number of patterned "Japanese fashion face masks" available--flowers and manga faces and roaring mouths, even just bold plain colours. There's a discussion here, with what passes for survey data in the fashion industry, and some illustrative pictures. You're not seeing this on the ground, I take it?
    Yes, and I wonder if the seriousness of the pandemic also plays a role in the sense that it may be more respectful and courteous to not give any fashion statement, especially if others only have white masks. I think the common courtesy point is a very reasonable one and a factor in any culture including the fashion aspects of the culture.
    We know time flies, we just can't see its wings.

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    Quote Originally Posted by Roger E. Moore View Post
    I wonder if having the virus settled on the outside of the mask would lead to it being inhaled through the mask fibers when the mask wearer breathes in.
    The ease of breathing with a bandanna is worth noting though it is inferior to a mask overall. With the bandanna, the air flow comes mostly from directly below so if distance is maintained it should prove beneficial, though I'm comparing it to using no mask nor covering.
    We know time flies, we just can't see its wings.

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    Quote Originally Posted by grant hutchison View Post
    News from the public briefing in the UK today is that the literature review carried out for the WHO (led by an academic in Hong Kong, interestingly) has concluded there is still no evidence that public mask wearing has any impact on the progress of an epidemic. I haven't found an official statement from the WHO yet, but I have no reason to doubt the reported conversation with the review chair.
    It's certainly the issue of the day. I would point out, however, that if correlation is not causation, it also holds that absence of evidence is not evidence of absence. It might be rather difficult to get evidence that wearing masks helps lower R0, all we know is what the Koreans are doing in total is extremely good at doing that.

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    Yeah, "absence of evidence is not evidence of absence" is commonly heard in this debate. It's what people always say when there is no evidence to support their position. But the fact remains that people have looked for evidence and not found it, over a period of twenty-five years that I'm aware of. That, in a funny old way, feels like evidence.

    Grant Hutchison

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    Quote Originally Posted by George View Post
    ...But in spite of all his rancor, he, near the end stated, "So, could hydroxychloroquine and chloroquine be effective drugs to treat and/or prevent COVID-19? Sure, it’s possible. There’s a plausible mechanism by which the drugs could inhibit viral replication (several, actually)....
    I find it somewhat odd that HCQ is a standard treatment for lupus, which is an autoimmune disorder where, AIUI, the body's immune system becomes hyperactive and attacks normal, healthy tissue. This says to me, which very well may be wrong, that HCQ must arrest this immune system hyperactivity. If HCQ "works" against Covid19, it must not disable the immune system entirely, otherwise one would think it would be an especially bad medication to take for Covid19, which you want the immune system to defeat, and quickly.

    I took a malaria medication when I lived in Africa (chloroquine? I forget). I didn't get malaria. A buddy of mine wasn't religious with taking the medication and got malaria. You don't want that! He survived but was very sick for a while. I have no idea what mechanism is in play with these drugs.
    Everyone is entitled to his own opinion, but not his own facts.

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    Absence of evidence isn't evidence of absence in situations where it would be hard to get the evidence, given that the situation is very difficult to control. I'd be convinced if I saw a study that had the kinds of controls you'd need. We can't exactly ask the Koreans to do everything but the masks for a month, and see if their cases rise. But we could easily ask somewhere in the west to keep doing what they are now doing, and also wear masks, and see if that helps make the cases drop, though even then we won't know if the drop would have happened anyway. What I would need to convince me that the Koreans are doing something that is not helping keep R0 down is actual evidence that it's not keeping R0 down, given that their R0 is down. Yes, it might be the other things they are doing, but I'm sure there are many elements of any given medical protocol that might not be part of the good prognosis, but they don't know it's not part of the good prognosis, so they keep doing it anyway-- so long as it's one of the more easy and cheap aspects of the protocol. And no doubt the reason they keep doing it is that they figure, if they are getting a good result, it certainly can't be hurting.
    Last edited by Ken G; 2020-Apr-04 at 12:18 AM.

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    Wearing any kind of mask gives me a cough for several days after usage.
    In my case, this could be humidity buildup, as changes in humdity triggered asthma attacks when I was young.
    Nonetheless, I'm covering up when I go out at the moment.

    Who says wearing them can't worsen R0 where asthma is common .. and given the lack of verifying study data?

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    We've kind of got "everything but the masks for a month" from the South Koreans, because they introduced mask rationing (two a week) three and a half weeks ago. No rise in cases. Now you could say that they could have driven their new case rate to zero (instead of 50-100/day) if they'd kept using masks at peak rate. Or you could say that the lack of a rebound in cases proves that masks are useful beyond what physical barrier testing suggests is realistic. Or you could say that not having a new mask for every day forces people to do better social distancing. Or you could say masks don't make a noticeable difference. Or you could say that the mass reuse of masks actually stops you getting down to zero cases.

    Grant Hutchison
    Last edited by grant hutchison; 2020-Apr-04 at 01:29 AM.

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    Re the 1918 pandemic:


    Harris was especially entertained by a directive requiring Seattle residents to wear masks in public. “Gee!” she wrote. “People will look funny—like ghosts.” She drew doodles of people in face masks in the margins of her diary and pasted in an article about the latest face-mask fashions.


    .....
    “It was almost like Don’t breathe in my face; don’t look at me and breathe in my face, because you may give me the germ that I don’t want, and you never knew from day to day who was going to be next on the death list.”
    Read: Photos of the 1918 flu pandemic
    ....
    After six weeks of lockdown, public gathering spaces in Seattle finally reopened for business. “School opens this week,” Harris wrote in her diary. “Thursday! Did you ever? As if they couldn’t have waited till Monday!”





    https://amp.theatlantic.com/amp/article/609163/

    The photos:

    https://www.theatlantic.com/photo/20...ndemic/557663/

    How little things change. Wash your hands:
    https://time.com/5810695/spanish-flu...-ads/?amp=true
    Last edited by a1call; 2020-Apr-04 at 01:42 AM.

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    Quote Originally Posted by Cougar View Post
    ... This says to me, which very well may be wrong, that HCQ must arrest this immune system hyperactivity....
    Come to think of it, not necessarily. Perhaps the HCQ somehow "shields" or coats the cells and tissues enough so that the virus is unable to attach, enter, and reproduce so easily, similar to the malaria parasite being unable to easily enter the red blood cells....... as well as making it more difficult for the immune system to attack the normal tissue (as with lupus)......
    Everyone is entitled to his own opinion, but not his own facts.

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    In case this site hasn't aleady been mentioned, it gives interesting mortality data for Europe: https://www.euromomo.eu/index.html
    Is there similar data online for regions of the USA?

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    Quote Originally Posted by tashirosgt View Post
    In case this site hasn't aleady been mentioned, it gives interesting mortality data for Europe: https://www.euromomo.eu/index.html
    Is there similar data online for regions of the USA?
    Is this a close match?
    Solfe

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    Quote Originally Posted by Solfe View Post
    Is this a close match?
    No, because it doesn't show mortality from all causes.

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    How COVID-19 has risen over time in different countries: the miracle of South Korea, the disaster of the United States.

    https://www.cnbc.com/2020/04/04/coro...countries.html
    Do good work. —Virgil Ivan "Gus" Grissom

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    Any comments on this article, that diarrhea is sometimes one of the first signs of COVID-19 infection?

    https://www.msn.com/en-us/health/med...ts/ar-BB11YvuK
    Do good work. —Virgil Ivan "Gus" Grissom

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    Quote Originally Posted by Roger E. Moore View Post
    Any comments on this article, that diarrhea is sometimes one of the first signs of COVID-19 infection?

    https://www.msn.com/en-us/health/med...ts/ar-BB11YvuK
    As the article says, that's by no means the first we've heard of it--we had that information coming out of China two months ago.
    The problem is that lower gut symptoms are extremely non-specific, and most people who develop gut symptoms therefore won't have COVID-19. But if you go on to develop fever and cough, then any premonitory diarrhoea will tend to push the clinical diagnosis towards COVID-19.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    As the article says, that's by no means the first we've heard of it--we had that information coming out of China two months ago. The problem is that lower gut symptoms are extremely non-specific, and most people who develop gut symptoms therefore won't have COVID-19. But if you go on to develop fever and cough, then any premonitory diarrhoea will tend to push the clinical diagnosis towards COVID-19. Grant Hutchison
    Ah, thanks. Got me thinking there.
    Do good work. —Virgil Ivan "Gus" Grissom

  23. #1493
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    Quote Originally Posted by Ken G View Post
    The Atlantic magazine has a good article about the current thinking on masks, at https://www.theatlantic.com/health/a...-masks/609235/. Here is a relevant quote:
    In the U.S., the CDC is reportedly contemplating a change in guidance, and many public-health experts have already pivoted. “I went with the public-health message at the beginning: People don’t need masks,” Marr said. “But I’ve changed because of the mounting evidence that it does seem to be spreading through the air.”
    Other doctors are not so sure. But I see obvious logical problems in statements like:
    "Other studies have been more equivocal, finding that masks provide no benefit, small benefits, or benefits only in conjunction with measures like hand-washing."
    The problem in the logic here is taking that statement, and interpreting "masks won't always work, and sometimes might not work at all" as meaning "so you shouldn't wear masks." And how about saying masks don't work well unless combined with handwashing? Just combine them with handwashing, for crying out loud.

    And the other thing is that there is not enough attention on the difference between masks protecting the wearer, versus protecting everyone else. I've even heard it said that the only people who should wear masks are those who are sick, which is obvious nonsense because many people won't know they are sick, or won't self identify as sick even when symptoms first begin. If we think a mask is protective of the public when worn by sick people, and we agree that sensible policy is to regard everyone as sick at all times when we make simple low-impact decisions like whether to get into an elevator with them or not, then obviously everyone should wear masks at all times in public. The issue of availability is not a reason to change that, it's a reason to be more intelligent about availability. (Make more, make a range of protection levels, use responsibly, don't hoard, etc.-- none of those say "don't wear masks.")
    Hearing about Japan will make an ongoing experiment. Japan has so far done little testing but has a culture of mask wearing and avoids handshakes. To this point they also have a low rate of disease but epidemiologists fear they have nursed an expansion in undetected infection and will now see the unfortunate effects in an unusually aged population.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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    Quote Originally Posted by grant hutchison View Post
    We've kind of got "everything but the masks for a month" from the South Koreans, because they introduced mask rationing (two a week) three and a half weeks ago.
    That's an interesting point, though two a week is not the same as no masks. I would not be against two-a-week limits in the US either, if it came with encouragement to wear masks-- and if we waited to do it until we had our cases down to what South Korea has. The main guiding principle is, do exactly what they did, to whatever extent we can. That's essentially the same policy as following a specific medical protocol, even when you don't know what aspects of that protocol are the most important to do, and you don't know why they work.

    For example, if the main thing masks do is limit the spread by asymptomatic people to others, then those people could literally wear the same mask for a month and it might still limit the spread by limiting the range of airborne particles. What's more, masks might be less important once you already have a daily death total you can count on one hand, as they do in South Korea, because when so few sick people are walking around, surfaces could become the main mode of transmission, as could people who are traveling from elsewhere.

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    Quote Originally Posted by Ken G View Post
    That's an interesting point, though two a week is not the same as no masks.
    Sure. But one of the cardinal tests of whether to believe a claim of causation is, "Is there a dose response?" In many public heath settings you can't change the dose to zero, but you can compare different levels of exposure.

    Quote Originally Posted by Ken G View Post
    What's more, masks might be less important once you already have a daily death total you can count on one hand, as they do in South Korea, because when so few sick people are walking around, surfaces could become the main mode of transmission, as could people who are traveling from elsewhere.
    But of course masks are extremely relevant to surface contamination, particularly if they're being reused. People contaminate their hands when handling the mask, or contaminate surfaces that the mask is laid on.

    Another feature of the mask rationing in South Korea is that they're now seeing people without masks queuing to buy masks.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    The problem is that lower gut symptoms are extremely non-specific, and most people who develop gut symptoms therefore won't have COVID-19. But if you go on to develop fever and cough, then any premonitory diarrhoea will tend to push the clinical diagnosis towards COVID-19.
    And there's also the problem of the impact of personal panic. I'll bet the majority of the people on this thread have at one point asked themself, "I wonder if I have it?" Often late at night, when we are emprisoned in our own thoughts and magnifying each tiny symptom. I have a headache, could this be it? These body aches are unusual for me, is this COVID-19? And now, any time anyone has diarrhea, they are going to get worried (digestive problems have been cited as something that happens more often in the severe cases, so it does raise some concern). Perhaps a little worry isn't a big deal, but it can lead to symptoms brought on by anxiety itself. I would think that the symptom of losing the sense of smell is the one that stands out, because that is so very unusual that it would be deeply concerning (though not if it remains the only symptom for a long time, that would be a good result!). Of course I wonder how many people can have that symptom from sheer anxiety, once they are told it is a symptom. Unfortunately anxiety is pretty good at mimicking just about anything. What would be nice to have is a first-stage suggested treatment that is of such low impact it can be used even when there is only the smallest suspicion of disease. I haven't really heard any suggestions of such a thing, though I might imagine setting up a humidifier and avoiding ibuprofen (is that still widely accepted as a danger?). And of course, stay home, but not everyone can do that. It has been pointed out that most of the things we are being told to do are actually manifestations of personal privilege (the privilege to be able to stay home, the privilege to have running water to wash hands, the privilege to be 6 feet away from everyone else at all times, etc.). So for those of us able to do these things, including self-quarantine at the slightest hint of disease, we should count ourselves lucky.

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    Quote Originally Posted by grant hutchison View Post
    Sure. But one of the cardinal tests of whether to believe a claim of causation is, "Is there a dose response?" In many public heath settings you can't change the dose to zero, but you can compare different levels of exposure.
    Another feature of the mask rationing in South Korea is that they're now seeing people without masks queuing to buy masks.
    I'm not suggesting that masks would have the kind of impact on R0 that you could tease out from small statistics in a few weeks, which is barely a single generation of the disease process. The question is, could it reduce R0 by 10%? It would be so worth it if it could, that equals the effect of 10% herd immunity, an immunity level which comes at the cost of some 100,000 lives in the US alone.

    I wonder why they are mask rationing at all? Their healthcare workers are not taxed at all, they have very few cases to deal with. Plus, it seems likely that people are still wearing masks just as often-- merely the same ones more times. There is so little contagion in South Korea right now that almost all those masks are clean anyway, and the people in those queues aren't sick. The issue is more about places like New Orleans or New York City-- and the question is, what effect would widespread mask usage have there? Maybe masks have more of an impact on a certain type of transmission that is only a dominant form when disease is more widespread (i.e., in an exponential phase). I still feel like there is something going on with this disease that we have not understood, because its tendency to show environment-specific differences in R0 seems to lead to local explosions. For example, what if masks are of greatest value in places that have a propensity toward crowds? In places that are currently avoiding crowds, the value of masks might not be evident, but are we really picturing a solution wherein we have no crowds for the next year? Since places like New York and New Orleans got out of control when there were crowds, how might that have been different if people had been encouraged to wear masks, instead of encouraged not to? Or perhaps, there are certain weather conditions where the disease tends to explode, and those might also be the situations where it is useful to have masks-- but not in situations where the weather is not conducive and the disease is not exploding. Or maybe, masks have no direct value at all, but do serve the purpose of being a constant reminder to the population to take it seriously and reduce R0-- a reminder badly needed by countries with zero history of concern about pandemics (in the US, we actually have anti-vaxxers, for example), but that South Korea no longer needs since they had a dry run with SARS.

    It all comes down to, what is different here from South Korea, and what part of those differences could be removed by removing the different attitude about masks. Maybe it's only a small part of the difference, but we need to think in terms of societal cost per 0.1 reduction in R0. Right now we have lots of resources going into making and staffing ventilators, which is needed in the hospital environment but from a societal standpoint, is not actually part of the solution because it has no effect on R0 and only reduces the death toll by perhaps a factor of 2. Attacking R0 directly on every possible front, especially economically sustainable ones, could reduce the death toll by a factor of 100 over the full course of the disease, as we develop the most sustainable strategies that work. Right now the stress is on doing whatever it takes to get the numbers down, which makes sense now, but sustainability will soon need to be part of the equation.
    Last edited by Ken G; 2020-Apr-04 at 04:40 PM.

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    Not sure if this was cited elsewhere in this thread, but here is a link to "a cluster randomised trial of cloth masks compared with medical masks in healthcare workers" conducted in Hanoi in 2015. Note that this is in a clinical setting and not in a wider community so it's a bit of apples to oranges.

    ObjectiveThe aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks.

    Setting

    14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam.

    Participants

    1607 hospital HCWs aged ≥18 years working full-time in selected high-risk wards.

    Intervention

    Hospital wards were randomised to: medical masks, cloth masks or a control group (usual practice, which included mask wearing). Participants used the mask on every shift for 4 consecutive weeks.

    Main outcome measure

    Clinical respiratory illness (CRI), influenza-like illness (ILI) and laboratory-confirmed respiratory virus infection.

    Results

    The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%.

    Conclusions

    This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.

  29. #1499
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    Quote Originally Posted by Ken G View Post
    I wonder why they are mask rationing at all?.
    Because they don't have enough masks. Even in a country in which mask-wearing was fairly common (though not in a majority) as part of its culture, and which has banned all mask export.
    There are not enough masks in the world to deliver any widespread programme of citizens wearing masks, and it appears that there won't be before the end of the year (3M figure they can make a billion N95s by the end of the year, which is a drop in the ocean if you imagine everyone wearing one every day) The ghastly international "mask wars" that are currently depriving health care professionals of masks reflects that reality.

    Grant Hutchison

  30. #1500
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    Quote Originally Posted by schlaugh View Post
    Not sure if this was cited elsewhere in this thread, but here is a link to "a cluster randomised trial of cloth masks compared with medical masks in healthcare workers" conducted in Hanoi in 2015. Note that this is in a clinical setting and not in a wider community so it's a bit of apples to oranges.
    Reinventing the wheel a little. The original research on cloth versus disposable paper medical masks was done back in the 1970s, when the paper ones were being introduced. (My old boss used to tell me, wearily, that if you worked in medicine long enough, everything came round again as "new research".)

    Grant Hutchison

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