Dr. Rochelle Walensky, director of the Centers for Disease Control, garnered much attention a couple of weeks ago when she declared, “Masks can help reduce your chance of #COVID19 infection by more than 80%.” That would be remarkable, if true. As one commentator noted, Dr. Walensky evidently believes that wearing masks is more effective than Johnson & Johnson’s vaccine and not vastly less effective than Pfizer’s or Moderna’s. If that’s really the case, is it wise to spend billions of dollars on a mass vaccination program and to threaten those who aren’t vaccinated with the loss of their livelihood? No one has brought forward a scintilla of evidence supporting Dr. Walensky’s statement. She apparently just pulled it out of the air, knowing that the “fact checkers” would nod and go back to scrutinizing satires posted by the Babylon Bee.
Quite a few studies of the efficacy of face masks in protecting against Covid-19 have been published. You can find summaries of their results here and here. A news report summarizes the evidence thus:
Of 16 randomized controlled trials comparing mask effectiveness to controls with no masks, 14 failed to find a statistically significant benefit, the researchers said. And of 16 quantitative meta-analyses, half showed weak evidence of mask effectiveness, while the others “were equivocal or critical as to whether evidence supports a public recommendation of masks,” they said.
“The biggest takeaway is that more than 100 years of attempts to prove that masks are beneficial has produced a large volume of mostly low-quality evidence that has generally failed to demonstrate their value in most settings,” Dr. Jonathan Darrow, an assistant professor of medicine at Harvard Medical School and one of the researchers, told The Epoch Times in an email.
“Officials mulling mask recommendations should turn their attention to interventions with larger and more certain benefits, such as vaccines. Based on the evidence currently available, masks are mostly a distraction from the important work of promoting public health.”
Of particular significance is the absence of any support at all for the notion that cloth masks, overwhelmingly the most frequently seen have any beneficial effect at all:
One study (pdf) that’s widely cited by mask proponents, of rural villages in Bangladesh, found that surgical masks appeared to be marginally effective in reducing symptomatic COVID-19 but that cloth masks weren’t, Darrow and his colleagues noted.
But what most impresses me is that the Food and Drug Administration, which ought to know a bit about public health, disagrees, albeit quietly, with Dr. Walensky on the mask issue. The FDA divides face coverings into four classes in increasing order of protection: face masks, barrier face coverings, surgical masks and N95 respirators.
Face masks (“a product that covers the wearer’s nose and mouth”, without meeting any more rigorous standard) “are for use as source control”, that is, to limit the exhalation of disease-causing organisms by infected persons, not to prevent uninfected persons from breathing them in. That the typical cloth mask serves the latter purpose very poorly is obvious. Look closely at masked people near you (trying not to stare impolitely), and you’ll see that almost all cloth masks are worn in a way that leaves ample access to whatever may be circulating in the atmosphere. Then place your own mask tightly over your mouth and breath in and out. It is barely more difficult than ordinary breathing. Even a surgical mask “does not filter or block very small particles in the air that may be transmitted by coughs, sneezes, or certain medical procedures”. Only properly worn N95 respirators furnish that protection, which, as the FDA notes, comes with the drawback of obstructing normal breathing, thus posing a danger to sufferers from “chronic respiratory, cardiac, or other medical conditions that make breathing difficult”.
If someone has contracted Covid-19, it makes sense for him to wear a face mask in order to reduce the risk of passing the illness along to others. Since, however, only a minute percentage of the population is infected at any particular time, and those who are transmit it with far less than 100 percent efficiency, that isn’t much of an argument for universal masking. There are doubtless circumstances in which masks are a prudent precaution, but “authorities” like Dr. Walensky show no interest in distinguishing those cases from the rest of life. Someday, I suppose, they will propose to reduce falls by compelling everyone to walk with the aid of crutches.
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