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Ironically, WHO and CDC have done bad messaging on both sides of this. I get slammed every time I bring this up now, because the issue is politicized and, let's

Ironically, WHO and CDC have done bad messaging on both sides of this. I get slammed every time I bring this up now, because the issue is politicized and, let's be honest, pretty traumatic as well. But I think it's important so I'll keep trying. Everyone should have been masking up as soon as possible in the pandemic. Case counts were low, we didn't know much about the route of transmission, and we also thought it was even more dangerous than it turned out to be. Precautions were indicated, but health authorities were decrying mask use as late as the end of March. But it turns out that the primary vector is aerosols, not droplets or fomites. Any mask will mitigate droplet contamination, and the resulting fomites: this is why influenza has practically disappeared, masking is very effective against influenza, where those are the primary vector. But no mask will do much to filter aerosols on exhalation. That's simply not how they work, positive pressure puts most of the gasses out through the sides of the mask. Even a P100 filter with cartridges won't do it, that's why they have a vent, otherwise the face seal would be broken every time one exhales. To be generous, I'll say that a cloth mask catches 30% of aerosols. It doesn't, but say it does: that's not nearly good enough. Which case counts after universal masking mandates illustrate quite clearly: they rise, and fall, and the masks don't have anything to do with it. A good mask will filter some aerosols when inhaling: but a cloth mask won't. So once aerosols were identified as the culprit, WHO and CDC should have emphasized air filtration, which is quite effective, limiting the number of people indoors on the basis of how many air exchanges a HEPA or ULPA filter was capable of doing. Messaging should have emphasized that cloth and surgical masks are completely useless, and that at-risk people should stay home, and if they can't, should get a proper mask (KN94, (K)N95, P100) and learn how to use it. COVID doesn't survive on surfaces very long, so reuse is more-or-less ok, and there were plenty of proper masks by June, which is when these facts were available. If WHO and CDC had listened to them. I vape, so I can illustrate this to myself quite easily: I can hit the vape through a cloth mask, but not a KN94. And with any mask, I can take a hit, put it on, and exhale a visible cloud of, yep, aerosols, around the side of the mask. I still wear a KN94 indoors, it's the best I can do. But I'm walking around in indoor spaces with no HEPA filters, surrounded by people who are unprotected, just wearing a talisman. This was preventable.

octodog 6y ago
Do you have any sources for cloth or surgical masks not working? The study in this article [0] is still in pre-print but it claims that a change to mandatory mask wearing was a critical factor in crushing the virus in Melbourne's second wave. I've seen some comments on HN that masks aren't effective but from what I've read and observed in Melbourne/Australia they have been very effective. [0] https://www.abc.net.au/news/2021-04-14/face-masks-number-one-in-pushing-down-victorian-covid19-cases/100065656 https://www.abc.net.au/news/2021-04-14/face-masks-number-one...
- samatman 6y ago
  See some sibling comments for my specific thoughts on the matter. Melbourne did everything they could think of, and the sum of it worked. This included a very severe lockdown, contact tracing, masking in the very limited public interactions which were allowed, and starting with a relatively low case count. I'm fairly confident that masks were the least important part of this, and that shutting down basically every part of public life was the most. I did say that masking early on was indicated, and that WHO and CDC failed us there. I sort of glossed over the part where case counts were low, but it's there, and it's pretty important. What the US and Europe needed early is what New Zealand and Australia (and Taiwan, Korea, maybe a couple other Southeast Asian countries) actually managed: universal masking, a nearly-complete cessation of public life, widespread testing, contact tracing, and central quarantine for the infected. Instead, we got dithering and "wash your hands". It was too late for that suite of interventions to be effective by 1st April at the latest. Earlier for Europe, which had the early wave epidemic in Italy. So of course, that's when masking was adopted, as a totemic symbol that the powers that be were "doing something". But we had crossed the point where it could help, and it was always the least important thing.
  - kelnos 6y ago
    > See some sibling comments for my specific thoughts on the matter. I took a look at your sibling comments, but I don't see any sources linked that suggest cloth masks are so ineffective as to be useless. Here are a couple studies suggesting they aren't useless (searched "cloth mask aerosol protection" via DDG): https://pubs.acs.org/doi/10.1021/acsnano.0c03252 https://pubs.acs.org/doi/10.1021/acsnano.0c03252 (effectiveness had a very wide range, depending on weave, thread count, etc.) https://www.nist.gov/publications/filtration-efficiencies-nanoscale-aerosol-cloth-mask-materials-used-protection-sars-cov https://www.nist.gov/publications/filtration-efficiencies-na... I get what you're saying in general, that "cloth mask" means many different things, and that those things aren't going to have the same levels of protection, but you seem to be pushing the idea -- without evidence -- that all cloth masks are worse than useless. Science doesn't seem to agree with you?

octodog 6y ago

Do you have any sources for cloth or surgical masks not working? The study in this article [0] is still in pre-print but it claims that a change to mandatory mask wearing was a critical factor in crushing the virus in Melbourne's second wave. I've seen some comments on HN that masks aren't effective but from what I've read and observed in Melbourne/Australia they have been very effective. [0] https://www.abc.net.au/news/2021-04-14/face-masks-number-one-in-pushing-down-victorian-covid19-cases/100065656 https://www.abc.net.au/news/2021-04-14/face-masks-number-one...

samatman 6y ago
See some sibling comments for my specific thoughts on the matter. Melbourne did everything they could think of, and the sum of it worked. This included a very severe lockdown, contact tracing, masking in the very limited public interactions which were allowed, and starting with a relatively low case count. I'm fairly confident that masks were the least important part of this, and that shutting down basically every part of public life was the most. I did say that masking early on was indicated, and that WHO and CDC failed us there. I sort of glossed over the part where case counts were low, but it's there, and it's pretty important. What the US and Europe needed early is what New Zealand and Australia (and Taiwan, Korea, maybe a couple other Southeast Asian countries) actually managed: universal masking, a nearly-complete cessation of public life, widespread testing, contact tracing, and central quarantine for the infected. Instead, we got dithering and "wash your hands". It was too late for that suite of interventions to be effective by 1st April at the latest. Earlier for Europe, which had the early wave epidemic in Italy. So of course, that's when masking was adopted, as a totemic symbol that the powers that be were "doing something". But we had crossed the point where it could help, and it was always the least important thing.
- kelnos 6y ago
  > See some sibling comments for my specific thoughts on the matter. I took a look at your sibling comments, but I don't see any sources linked that suggest cloth masks are so ineffective as to be useless. Here are a couple studies suggesting they aren't useless (searched "cloth mask aerosol protection" via DDG): https://pubs.acs.org/doi/10.1021/acsnano.0c03252 https://pubs.acs.org/doi/10.1021/acsnano.0c03252 (effectiveness had a very wide range, depending on weave, thread count, etc.) https://www.nist.gov/publications/filtration-efficiencies-nanoscale-aerosol-cloth-mask-materials-used-protection-sars-cov https://www.nist.gov/publications/filtration-efficiencies-na... I get what you're saying in general, that "cloth mask" means many different things, and that those things aren't going to have the same levels of protection, but you seem to be pushing the idea -- without evidence -- that all cloth masks are worse than useless. Science doesn't seem to agree with you?