Advice on mask-wearing to protect against Covid-19

Discussion in 'Epidemics (including Covid-19, not Long Covid)' started by Hip, Apr 2, 2020.

  1. rvallee

    rvallee Senior Member (Voting Rights)

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    It's been frustrating seeing other countries missing out on the lessons from China. I'm just a disabled nobody with access to the Internet and I was watching videos straight from Wuhan while it was happening and it was obvious what was coming and what must be done to stamp it out, no need to ask anyone's opinion on this. Intelligence services all over the world had access to the same and concluded the same but somehow governments decided to disbelieve it, even bury the worst-case scenarios.

    China did not do a coercive lockdown of Wuhan for the heck of it. They did it because it's the only containment strategy that works. Along with masks, test-test-and-retest and spraying whatever it is they spray all over infected cities. We then saw other countries in the region do the same and have some success at it. Doesn't take a PhD in being smart to get the damn message. We don't need to weld people shut in their apartments but then it's just a measure of how to enforce the policies, not what policies to adopt.

    There is a blueprint. Nobody should have needed people guiding their hands, other governments only had to pay attention to the actions taken, they literally only needed Internet access to see most of it. To think that Chinese government officials took the actions they did out of some Chinese exceptionalism is seriously hubristic.

    So absolutely face masks are a must. This is a multi-systemic problem that requires a multi-systemic set of solutions. There is no silver bullet, no easy way out. Which we unfortunately know all about isn't humanity's strong suit.
     
    Last edited by a moderator: Apr 3, 2020
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  2. ahimsa

    ahimsa Senior Member (Voting Rights)

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    Last edited: Apr 3, 2020
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  3. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    I like Herd Protection.

    Another neologism that occurred to me earlier today is Pagliocracy (government by clowns)

    Edit: Maybe it should be Pagliacciocracy but that sounds silly.
    Edit: The original Greek should be Paliatsocracy I guess.
     
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  4. Hip

    Hip Senior Member (Voting Rights)

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    Here is the self-contradictory statement by the US Surgeon General, tweeted 29 Feb 2020:
    Source: here

    So somehow when medical staff wear masks, it protects them from coronavirus; but when the general public wear them, it does not work.

    For the general public, according to dubious advice in circulation, masks only stop other people from catching your coronavirus infection, but masks do not stop you from catching the virus.

    Only if you are a doctor or nurse does the mask stop you from catching it!

    Obviously that makes little sense.



    Sure, medical staff tending to coronavirus patients have much higher exposure levels to coronavirus, so they should get masks as a priority. But clearly if it works for them, it will work for everyone.

    Advice like this has set us back by at least a month in terms of ramping up face mask production to supply the general public.
     
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  5. Leila

    Leila Senior Member (Voting Rights)

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    Especially considering that a large part of the population is expected to be infected.

    So even if we take that argument that they only are helpful when you are closely dealing with an infected person, chances are high somebody in your household will get sick. By then you definetely need a mask for the sick and the healthy at home I think.
     
  6. wigglethemouse

    wigglethemouse Senior Member (Voting Rights)

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    Several counties in California are now recommending public wear masks. The biggest was the LA mayor. The governor of California states face coverings can help but won't mandate right now.
    https://www.latimes.com/california/...ings-can-help-but-california-wont-mandate-now
     
  7. Snow Leopard

    Snow Leopard Senior Member (Voting Rights)

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    The mask isn't necessarily there to protect them from the virus, it's to protect us from the medical practitioners who have been exposed to the virus and might be presymptomatic carriers.
     
  8. Hip

    Hip Senior Member (Voting Rights)

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    Another advantage maybe, but that is not what the press and medical reports are saying: they are saying the lives of frontline hospital workers are put at risk because of a dire shortage of masks and other equipment which protects them.

    For example, see this article:
    'I'm full of dread': Doctors, nurses and cleaners on risking their lives for their job

    And the WHO themselves say:
    Shortage of personal protective equipment endangering health workers worldwide

    So far, 66 doctors have died from coronavirus in Italy because they have not got protective equipment. Ref: here. And in the UK, 4 medical staff have died from coronavirus so far, and no doubt there will be sadly many more.

    Thus the threat to the lives of medical staff is real.



    In the NHS, doctors and staff have been told by NHS management not to speak to the media, or detail on social media, the dire situation of mask shortages, with threats of consequences for their careers if they do:

    NHS staff 'gagged' over coronavirus shortages
    I suspect some senior NHS or UK government officials are covering their own arses after screwing up very badly on this issue of the supply of protective equipment.

    I cannot see any reason why you would want to hush up a mask shortage, other than arse covering. Normally if you have problem, you welcome the publicity, as it often results in other institutions offering help. But NHS senior management it seems want to sweep this problem under the carpet.

    The UK is acting in a manner not so far removed from China when it comes to silencing medical staff.

    We all saw the coronavirus outbreak in Wuhan back in January. The NHS is fully aware of the dangers of pandemics, yet nobody in NHS senior management thought to make sure their medical staff had enough protective equipment.

    Whereas in Taiwan, they saw this pandemic coming from miles away, and opened over 60 new production lines to make masks, so that not only medics, but everyone in the country was well supplied with face masks.
     
    Last edited: Apr 3, 2020
  9. Sean

    Sean Moderator Staff Member

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    Two different categories of masks in play here.

    One is the high-grade kind required to properly protect medical staff who are being constantly exposed at close quarters. The other is the more basic surgical mask kind to help stop it being transmitted out in the general public who can keep their distance from each other and so are not being constantly exposed at close quarters.

    The first one is the (hopefully) 100% effective type. The second is the greatly reduces the odds type.

    The first one is highly specialised, expensive, and in limited supply. The second is generic, cheap, and easy to make in large numbers.
     
  10. Wonko

    Wonko Senior Member (Voting Rights)

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    The first one is, by definition, assumed to be 95% effective, if used correctly. To be more precise it is assumed to block 95% of the things it says it does so as to reduce exposure to 'manageable' levels. Not designed for virus protection but would help limit exposure.

    Which is why people who work with dangerous viruses use an entirely different setup. Involving positive pressure to make sure that no airflow can enter the suit.
     
  11. Hip

    Hip Senior Member (Voting Rights)

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    You are referring to surgical masks (which normal cost a penny a piece) versus respirator masks (normally about 50 pence each), such as the FFP2-grade respirator (or US equivalent N95-grade respirator).

    It's been widely said in the media that surgical masks only protect other people, as they stop infected people from ejecting infected spittle from their mouth; and it is said surgical masks do not stop you from picking up an infection from others.

    However, this might be misleading information, as the study I mentioned in the first post found that there was virtually no difference between surgical masks and respirators in their ability to prevent medical staff from contracting influenzavirus in a hospital looking after influenza patients.

    That study demonstrates cheap surgical masks are just as good as respirators in protecting the wearer from a contagious viral infection.

    Possibly this idea that surgical masks do not protect you was put out in the media to stop people panic buying masks, to protect the supply of masks for frontline workers.

    I think this misleading information is dangerous, because our leaders and politicians are also duped by it, and so nobody is thinking in terms of mass production of surgical masks for the populace, a strategy which could help halt this pandemic.



    With masks, they talk about filtration efficiency for tiny viral particles, with the N95 respirator mask being 95% efficient, and the N99 being 99% efficient.

    However, as I said earlier, filtration of viral particles is not the only function of a mask: a mask will also stop you from touching your mouth and nose, which helps prevent viral transmission.

    And even a surgical mask will stop large droplets that are ballistically ejected from an infected person's mouth from directly landing on your mouth and nose. Plus if you yourself are infected, a surgical mask stops you from ballistically ejecting such droplets in the first place.

    By ballistic ejection, we mean large droplets of spittle or mucous that are ejected from the mouth or nose, and follow a ballistic trajectory (ie, quickly fall to the ground under gravity). These ballistically ejected droplets usually only have a short range of a meter or so.

    You do not need a mask with a high filtration efficiency to stop ballistically ejected droplets, because the droplets are large, and even a course material like a cotton T-shirt will stop them.

    It's only the very small droplets which float in the air for hours that require a mask with good filtration efficiency.

    But remember, to stop an pandemic you do not need 100% protection; you just have to reduce the transmission so that each infected person on average infects less than 1 other person. Then the pandemic will automatically die out.

    For more info on respiratory droplet size and ejection, see this post.
     
    Last edited: Apr 3, 2020
  12. Leila

    Leila Senior Member (Voting Rights)

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    From today

    "Respiratory virus shedding in exhaled breath and efficacy of face masks"

    "We identified seasonal human coronaviruses, influenza viruses and rhinoviruses in exhaled breath and coughs of children and adults with acute respiratory illness.

    Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets.

    Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals."
     
  13. Hip

    Hip Senior Member (Voting Rights)

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    Good article by Business Insider:

    Countries, cities, and health authorities all over the world are reconsidering their coronavirus advice that most people don't need to wear masks


    Meanwhile, back in behind the curve Britain, an expert on the BBC still says today that:
     
    Last edited: Apr 3, 2020
  14. Leila

    Leila Senior Member (Voting Rights)

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    It's strange how much officials are tip toeing around the subject. They don't want people to get a false sense of security thinking with a mask they can come closer or they would harm themselves by putting it on and off the wrong way.

    Isn't that something that can be communicated and learnt though? We take part in traffic everyday and have learnt the rules to be as safe as possible.

    Things seem to change here . 2 weeks ago I was laughed at by my mailman because I was wearing a paper mask. Now he's waering an N95.
     
  15. Hip

    Hip Senior Member (Voting Rights)

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    Yes, a lot of the time we don't like to follow precautions because we are afraid to look silly. A few weeks ago, I tried to get my elderly parents to wear surgical masks when going to the supermarket, but they did not feel comfortable with it, because at that stage, very few people were wearing masks.

    But now in my suburb of London, about a quarter of the people you see in the street are wearing masks, so it has become normal. So now they are happy to wear a mask.
     
  16. Leila

    Leila Senior Member (Voting Rights)

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    And we got used to all sorts of silly trends. Like mullets etc. People can adapt :)

    I think with the right narrative which also is fact based - "I'm wearing this to protect you in case I'm sick" - this can become a new normal for some time.
     
  17. Wonko

    Wonko Senior Member (Voting Rights)

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    History suggest that what frightened people tend to pick up from "I'm wearing this to protect you in case I'm sick" is

    "I'm different and also sick - use cleansing fire on me immediately otherwise I'll infect you and your family"

    People are not always rational when afraid.
     
  18. Leila

    Leila Senior Member (Voting Rights)

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    Maybe that comparison is too far fetched but doesn't the same rationale apply like in safer sex?

    If two people don't know their own and the other person's status - and you can't get testet - wear protection.

    But I get what you mean. You could end up being chased with a pitchfork or a plague cross on your door...figuratively. I think this will change though the longer the situation will last.
     
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  19. Hip

    Hip Senior Member (Voting Rights)

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    I wrote to the Guardian yesterday, detailing much I what was included in the first post of this thread, and today (3 April) there are two new articles in the Guardian examining the effectiveness of face masks:

    The first article points out that wearing a mask may produce a fivefold reduction in the chances of caching a virus (that's how I interpreted it — the article mentions "fivefold protection").

    See: Can a face mask protect me from coronavirus? Covid-19 myths busted

    Well, if the basic reproduction number (BRN) of the coronavirus is 2 to 3, as has been suggested (meaning each infected person goes on to infect 2 or 3 others on average), then a fivefold reduction in infection will reduce the BRN down to 3 ÷ 5 = 0.6 or less — which means the pandemic will die out, because pandemics fizzle out when BRN is less than 1.

    So it does not take a genius to work out that wearing masks may be the single most effective intervention we can make.
     
  20. Forbin

    Forbin Senior Member (Voting Rights)

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    In his recent interview on TWIV (@ 32:30) Ian Lipkin spoke about a small 2003 study in Beijing on whether face masks (surgical or N95) had a "dramatic" impact on community transmission.

    Despite the small study size, he found the results "compelling" because there was a "dose response." People who wore masks consistently had a 70% reduction in community transmission, while those who used them intermittently had only a 60% reduction. He considered trying to publish this, but decided that it might lead to shortages of masks at the "front lines."


    It's hard to say, but the fact that the study included both surgical and N95 masks suggests to me that a fair amount of the value in wearing a mask may simply come from the fact that doing so keeps you from touching your own face (except for your eyes).
     

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