The wearing of masks to prevent the spread of COVID-19 and other respiratory illnesses had almost no effect at the societal level, according to a rigorous new review of the available research.
"Interestingly, 12 trials in the review, ten in the community and two among healthcare workers, found that wearing masks in the community probably makes little or no difference to influenza-like or COVID-19-like illness transmission," writes Tom Jefferson, a British epidemiologist and co-author of the Cochrane Library's new report on masking trials. "Equally, the review found that masks had no effect on laboratory-confirmed influenza or SARS-CoV-2 outcomes. Five other trials showed no difference between one type of mask over another."
That finding is significant, given how comprehensive Cochrane's review was. The randomized control trials had hundreds of thousands of participants, and made useful comparisons: people who received masks—and, according to self-reporting, actually wore them—versus people who did not. Other studies that have tried to uncover the efficacy of mask requirements have tended to compare one municipality with another, without taking into account relevant differences between the groups. This was true of an infamous study of masking in Arizona schools conducted at the county level; the findings were cited by the Centers for Disease Control and Prevention (CDC) as reason to keep mask mandates in place.
"Comparing Pima and Maricopa counties is a pointless way to study masks—because the people are fundamentally different—apart from masking," noted Vinay Prasad, an epidemiologist who has opposed COVID-19 mandates. "They have different rates of vaccination and different levels of caution."
Cochrane employed randomized control trials (RCTs), which are considered the gold standard for review. And the results are inarguable: Zoom out to the population level, and masks had a scarcely discernible impact on COVID-19 cases.
"The pooled results of RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks," write the authors. "There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection."
David Zweig, a writer who helped call attention to the flaws in the Arizona study, noted that these negative findings reflect basic reality: While individual mask wearers might get some benefit for a while if they consistently, perfectly wear masks, this does not comport with the aggregate experience. According to Zweig:
Even the most ardent mask supporters, who want to wear them properly, fail to do so. And, as this study and others illustrate, even when masks are required they are either not worn properly, or not worn at all by a significant number of people. These images from a NY Times article comically show that children are no exception to this problem. And nor are teachers — this study, published by the CDC, on a school outbreak encapsulates the problem quite well: "the teacher read aloud unmasked to the class despite school requirements to mask while indoors."
Succinctly, Benjamin Recht, a statistician at UC Berkeley, who co-authored a re-analysis of the Bangladesh RCT, which negated that trial's findings, said: "At this point, I doubt any study will change anyone's mind about masking. But the one consistent finding of all of the randomized studies is that the effect of this intervention at the population level is vanishingly small."
The findings have yet to penetrate the mainstream media's bubble: Whereas flawed studies like the Arizona one received rave reviews in the pages of The New York Times and The Washington Post, so far the Cochrane review has not attracted coverage from these outlets. Nor has it garnered commentary from the CDC—an agency that has routinely seized on less compelling evidence in order to recommend the maintenance of intrusive COVID-19 interventions like mask mandates and lockdowns.
Indeed, while mask mandates are no longer a typical part of American life, there are still enclaves that require masking. Some U.S. schools have kept mask mandates in place, or brought them back during flu season. Within the nation's capital, George Washington University still requires masks in classrooms.
If following the science means updating one's priors when new evidence becomes available, then institutions that require masks should finally concede—three years into the pandemic—that indefinitely forcing them on unwilling people, especially children, is not a defensible strategy. As for any lingering government requirements, let this be the final and long overdue word: no more mandates.
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