Monday, April 27, 2020

Face masks DO protect the wearer as well as others

Well, I hate to say I told you so ... but finally there is an article by a reputable epidemiologist saying what I have been saying for some time now, namely that face masks are just as good at keeping the virus out as keeping it in.
Felix Li spent 23 years as an epidemiologist and public health specialist at the Public Health Agency of Canada (PHAC), including 7 years working for PHAC in China (he is now retired, but don't hold that against him). Anyway, my point is: he knows whereof he speaks.
The use of face masks by the general public during the COVID-19 pandemic has undergone something of an evolution, you might say, from "don't bother, they're completely useless" to "wear them if it makes you feel better, no harm done" to "they might prevent you from spreading the virus to other people, but don't expect them to protect you" to "actually, yeah, wear them whenever you are in potential contact with other people, they could be very useful".
But the general view, or impression given, is still that they are more likely to protect others than they are to protect the wearer, a contention that has never made any logical sense to me. Healthcare workers, on the other hand, are told that wearing a mask can protect them as well as their patients.
Now, I understand that the masks used by healthcare workers are better than the homemade cloth ones we of the hoi polloi wear. But surely the same principle applies: any mask will, to the extent its design allows, protect the wearer against droplet-transmitted diseases like COVID-19, just as it will protect others from the cough or "moist talking" of the wearer. And, yes, a mask may be itchy and cause people to scratch their faces, but it will also, to at least as great a degree, stop a person's potentially infected fingers from actually going into their mouth or nose.
To say that the general public is at a lower risk of exposure than a healthcare worker is obvious, but that is no reason to discourage them from reducing their own risks still further. If you need more convincing, read up on the "prevention paradox", a concept explained by eminent British epidemiologist Geoffrey Rose: simply put, reducing the low risks of the general population can be more effective at controlling an epidemic than concentrating on reducing the much higher risk of small sub-populations (like healthcare workers, for example), because the vast majority of cases actually originate from the large low-risk groups. Makes sense to me.
So, thank you Mr. Li for airing this, and for convincing me that common sense is actually useful after all.

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