With the masks, I am seeing and hearing more medical professionals (including my own providers) recommend double-masking, with KN94 or 95 plus a mask over. Basically layered protection.
Two interesting things:
And this:
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This is a rather old article (measured in “pandemic time”). Nevertheless, interesting information. I didn’t realize that masks protected the wearer from airborne virus by as much as 65%. That’s pretty decent protection. (I thought it was more like 35% for mist aerosols, or thereabouts.) Do you know of any more recent updates, or is it still pretty much the same?
The precise amount masks reduce whose risks seems academic when it’s indisputable that they work.
Well, if masks protect the wearer by 65%, that’s about as good as a vaccine.
Not at all. Masks are like sunscreen, they increase how much you can be exposed to without getting an infectious dose. You can handle a higher concentration of virus particles, or the same concentration for a longer time.
A vaccine that’s 65% effective would entirely protect 65% of people who get it from infection. The other 35% could get infected but might have milder cases than they would have otherwise.
Points taken and understood. But if all susceptible and all infectious wear masks, isn’t it like Honkman’s graphic (above), bottom row? Masks worn by all, within reason = vaccine?
In other words, when a vaccine is available to all next year (maybe), we won’t need masks, which, for now, have the same effective benefit.
Masks + minimizing time indoors with people who aren’t members of your household + keeping your distance outside reduces your risk to close to zero so long as all members of your household do it.
If people are sharing a stuffy indoor space for hours and one of them is contagious, enough virus particles may eventually get through the masks to infect most of them.
OK, well sure, I fully agree.
I guess what I was getting at is that if masks protect a susceptible person from 65% of airborne mists, and if masks capture the release of, let’s say 90% (a guess) of airborne mists expelled from the nose and mouth of an infected person, then the fraction of that 35% of mist that gets past the susceptible person’s mask effectively drops by 90% to just 4%. Which is to say, if all were wearing masks, there is then a 96% reduction in the amount of virus inhaled by susceptible people over any given length of time, compared to all being mask-less (65% + 90% of 35%). That’s a very high level of protection.
I see masks as a stopgap, a stand-in between the present (no vaccine) and the time when a safe vaccine has finally been released and fully distributed, and all possible inoculations administered.
Beyond that, masks should no longer be needed. My point is that wearing masks is the closest we can get to a vaccine right now.
But yes, if one remains within the kind of environment you described (stuffy indoor space), then even with only a 4% chance of virus getting past both barriers (masks), you could eventually get a infectious dose. But “eventually” would be a very long time.
In the real world, in some jobs, everybody’s wearing masks and there are still outbreaks.
That’s hard to understand unless they don’t actually wear the masks all the time, all day. In any event, in the real world, not everyone is wearing masks when they’re around others, and not everyone will get the vaccine when it’s available. So the end game will be a combination of natural and vaccine herd immunity, hopefully including adaptive T-cell immune response.
Based on what I’ve observed with people walking in our neighborhood (I haven’t set foot in a public building since the end of March/beginning of April), I think it’s likely people are wearing different types of masks (everything from the N95s through the layered paper/surgical masks, cloth masks, bandanas, and so forth). Guidance has been to “wear masks” but doesn’t spell-out (that I have seen) what type of mask.
Likewise, how they are wearing the mask (is it pinched closed over the nose and tight around the chin, etc.) is going to impact efficacy.
Further, even while wearing masks, people constantly touch their face: brushing back hair, scratching their cheek, adjusting glasses, adjusting their mask, pulling off mask to blow their nose, wipe off sweat, and a myriad of other things.
All of those are vulnerability points to acquire and spread the virus.
It’s very simple: if masks cut virus particles by 90-95%, it will take 10-20 times as long to get a critical mass to cause infection. Based on real-world cases, when people work together for a whole shift, that’s sometimes long enough.
Around here, I’ve seen signs that say something like “masks required, no valves.”
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Beside what was already mentioned (mask don’t protect 100% even when worn all the time) there is also indication that the virus can be transmitted through the eye (which isn’t protected by a mask)
That’s news to me. I know you can get infected by touching a heavily contaminated surface and then rubbing your eyes. But if I understand you correctly, I think you’re saying that you can also get infected by airborne mists that land on your eyes? That’s pretty scary, if true, and there’s not much that can be done about it (short of goggles…).
Contact tracing has not yet turned up a single case of being infected with SARS-CoV-2 from a surface.
That’s good news, but again, news to me. Perhaps the heavily-contaminated surfaces I’d heard about were ones in which somebody directly sneezed on them, in an experiment, and the mode of infection inferred.
Recently, I’ve read a number of news articles in which scientists have downplayed the significance of surface transmission. With caveats.
Well, if surfaces aren’t a meaningful source of infection, we can stop sanitizing shopping carts, etc. And, what’s then the problem with buffets and salad bars?
This is very powerful info, so I went looking for your source. For anybody else that is looking for a source, here is the WHO:
https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions
Despite consistent evidence as to SARS-CoV-2 contamination of surfaces and the survival of the virus on certain surfaces, there are no specific reports which have directly demonstrated fomite transmission.
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