[9oliYQjP]

I hear you and understand in theory things like surgical masks allow coronaviruses to pass through them. But we've got to stop thinking about wearing masks in absolute terms of "it works" or "it doesn't work". Just like computer security, wearing a mask is one layer of protection. I don't think any reasonable person expects a mask to be foolproof. But when used in conjunction with thorough and frequent hand washing and social distancing measures, I suspect we'll find that wearing a mask is a prudent thing to do, even if it's just a home-made one out of cotton pillowcases or a surgical mask. Masks should not be relied upon in the absence of social distancing and hand washing just as airbags should not be relied upon without wearing a seatbelt.

There's anecdotal evidence from places like Taiwan and Hong Kong that masks are somewhat helpful and very little real evidence that they're harmful except in terms of making masks unavailable to frontline health workers. I firmly believe that in hindsight, public health agencies in the west will realize they did a lot of harm by saying masks were worthless.

[pjscott]

Exactly: protection is probabilistic. Hand-washing isn't perfect, social distancing isn't perfect, and therefore in a sense you could say that they also "don't work" -- but they work in the sense that matters, i.e. reducing the spread of the virus.

[DanBC]

> But we've got to stop thinking about wearing masks in absolute terms of "it works" or "it doesn't work".

We're not saying that. We're saying masks make you touch your face, and that without training and correct fitting the minimal protection they give is probably countered by the increased risk.

https://www.nih.gov/news-events/news-releases/new-coronaviru...

> If the viability of the two coronaviruses is similar, why is SARS-CoV-2 resulting in more cases? Emerging evidence suggests that people infected with SARS-CoV-2 might be spreading virus without recognizing, or prior to recognizing, symptoms. This would make disease control measures that were effective against SARS-CoV-1 less effective against its successor.

https://www.nejm.org/doi/10.1056/NEJMc2004973

> We found that the stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested. This indicates that differences in the epidemiologic characteristics of these viruses probably arise from other factors, including high viral loads in the upper respiratory tract and the potential for persons infected with SARS-CoV-2 to shed and transmit the virus while asymptomatic.3,4 Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed). These findings echo those with SARS-CoV-1, in which these forms of transmission were associated with nosocomial spread and super-spreading events,5 and they provide information for pandemic mitigation efforts.

[9oliYQjP]

I keep hearing that masks make people touch their face. I put to you the following questions:

1. Do frontline healthcare workers also "touch [their] face" when wearing these masks for the same reasons regular people do? I imagine it's to adjust the fit? If the answer is no, is it because they have been educated not to? People, at least where I am in Canada, are being told not to touch our faces already. Can we not just extend the messaging to be "avoid touching your face, even when wearing a mask"?

2. If increased face touching when wearing a mask is truly a problem, would we not expect Hong Kong and Taiwan to have a worse community spread situation? Why is it that they have this contained? Again, the example is anecdotal. But coincidentally, they're both locations that learned from SARS and H1N1 and mask wearing is a foundational part of their public health response.