The Cochrane group recently produced a report that includes the following words: “Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks.” The Cochrane group is a global network of scientists and others who study the best evidence from research to determine whether treatments actually work. They have 37,000 contributors from more than 130 countries who work together to produce credible health information free from commercial sponsorship.
For the mask study, the researchers pored through published
studies, selecting only those that meet their requirements for reliability. They
select only randomized controlled trials—a way to examine cause-effect
relationships between an intervention and outcome. For the mask trials, the
researchers used 12 trials (276,917 participants) that compared those who wore
medical/surgical masks with those who did not.
One of he report’s authors told a reporter that “there is
just no evidence that they make any difference.” The Cochrane report itself includes the
following statement: “There is uncertainty about the effects of face masks. The
low to moderate certainty of evidence means our confidence in the effect
estimate is limited.” Nevertheless, the report does, finally, state, “The
pooled results of randomized controlled trials did not show a clear reduction in
respiratory viral infection with the use of medical/surgical masks.” In the
end, they say, more and better studies are needed.
As you can imagine, there's been blowback about this result, which appeared in The New York Times. Some people involved with the Cochrane organization have issued qualifying statements, saying that the wording in the report was open to misinterpretation, and that the review couldn't arrive at a firm conclusion because there weren't enough high-quality randomized trials with high rates of mask adherence.
As one who wears a mask only when required, I rather like
the study’s conclusion. On the other hand, I have no gripe with those who have
mandated mask-wearing. They were working with the best information available
and were taking no chances. Maybe they were right, maybe not.
For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.
I understand the difficulty of performing good randomized controlled studies in this case. Someone recently told me that Florida has a high rate of Covid; our governor has denied mandates for using the mask. I need to check if this comment is actually a fact.
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