Here's what used to be the conventional wisdom about masks in the pandemic:
1. Any mask that covers your nose and mouth is much better than no mask.
2. A cloth mask is better at preventing you from breathing out virus (if you have it) than at keeping you from breathing it in, but it helps enough with the latter to be worth the trouble.
3. An N95 mask does not offer much additional protection unless you fit it properly.
3a. And even people who wear N95s regularly, like health care workers, mostly do not know how to fit the mask properly.
4. If you do fit the mask properly, it will be so tight over your nose and mouth that you'll have trouble breathing, especially if you're exerting yourself. Another reason not to wear one.
4a. If you have a beard, forget it. The N95 will not have a tight enough fit.
Here's the current conventional wisdom about masks:
1. Cloth masks are almost completely useless. They're "mask theater."
2. An N95 is the minimum necessary prevention. Nothing about the difficulty of proper fitting. Just make sure you have the straps around your head in the correct manner.
What I want to know is, why did the conventional wisdom change? That it has changed, and that there are official pronouncements to back this up, is amply documented. That's not what I'm looking for. I want to know why the change.
I can think of some possible reasons:
1. The increased transmissibility of the omicron variant has changed the dynamics of risk.
2. New studies have overturned what we thought we knew.
3. The old thinking was folk-wisdom to begin with, and was never valid.
4. The new thinking is the result of hysteria or improper influence (like the reduction of isolation periods from 10 to 5 days) and isn't valid.
But which, if any, of these is true has not been discussed anywhere that I've seen it. Indeed, the old wisdom seems to have disappeared in enlightened circles as if it never existed at all. What's going on here?
What are you using as your sources for your description of conventional wisdom? I just looked at the CDC section on masks and COVID-19, and it is significantly different in some ways from your summary.
ReplyDeleteTo the best of my knowledge, there is nothing above an N95 available outside of VERY specialized environments. That statement would eliminate the use of KN95 or surgical masks, which doesn't fit with what I'm eeeing as "conventional wisdom" in some media sources.
This post is about the conventional wisdom, not the CDC guidelines, which look very out of date.
DeleteBut what I would describe as the conventional wisdom that I'm seeing in various sources (not CDC) or what I hear people talking about is very different from what you describe. Is "conventional wisdom" in this case a function of region of the country? That's not included in your list of possibilities.
DeleteRegion of the country? This is stuff B. and I are reading online; it comes from all over. Just a couple days ago she showed me a chart which I guess came from FB, giving statistics on how ineffective cloth masks are and how effective N95s are by comparison. I don't know what to make of this, but it's there.
DeleteYou haven't said what the conventional wisdom is that you're hearing, except to say that KN95s are not available to general use. That's not true; B. bought some online.
I should have been clearer in my original comment; when I wrote “That statement would eliminate the use of KN95 or surgical masks…” what I was thinking of and trying to refer to was your statement “An N95 is the minimum necessary prevention.” Sorry for the lack of clarity on my part. If N95 is minimum necessary protection, then KN95 and surgical masks don’t meet that standard. Those are both types of masks that I have seen recommended in a number of articles (and I checked tonight).
ReplyDeleteSingle layer cloth masks are clearly not acceptable in terms of providing protection; I would agree with the phrase “mask theater.” It’s less clear to me what the effectiveness is for cloth masks constructed from three or more layers of fabric. That’s not to suggest that three layer cloth masks are as effective as KN95, N95, or surgical masks. But are three-layer cloth masks so ineffective that they are nothing more than “mask theater?” I had to wear a disposable surgical mask earlier tonight and I found that didn’t fit as snugly as a multi-layer cloth mask that I’ve been using at work. I also did a quick “hard breath test” to confirm the difference in fit/seal. Obviously, neither of the masks I just referred to are as effective as N95 masks…but if the message becomes “N95 or nothing”, my concern is that the result will be a clear reduction in the percentage of people wearing masks. And that is CLEARLY not a good thing.
Your description of current “conventional wisdom” strikes me as a mixture of several factors:
- the greater transmissibility of omicron
- the thoughts/opinions of a finite number of individuals who have been interviewed by various media sources (article on the Today show website stated that their recommendations came from talking with two infectious disease specialists)
- new scientific studies (although it’s becoming harder to know when an article is referring to peer reviewed and published or a preprint)
- the subjective nature of risk perception
I thought the KN95 was more advanced than the N95, not less, and wrote on that basis. Now I'm confused.
DeleteBut if it's true, as the statistics B. was waving around say, that a cloth mask is useless, than "N95 or nothing" is not clearly a bad thing.
Now I see that you agree with the new conventional wisdom that a single cloth mask is useless, which is definitely not what the old conventional wisdom said. What I want to know is why the wisdom changed; we both listed possible reasons, which lists overlap; I want to know which of these was the actual reason.
I don't think the change is due to a single reason. Clearly omicron is more transmissible than earlier variants; the numbers that stick in my mind is that omicron looks to be twice as transmissible as delta, which was itself roughly twice as transmissible as the original virus. But that fact doesn't exclude other reasons that you and I listed. Which of those other reasons was part of the change will likely be much harder to pin down.
Delete