Masks make ‘no difference,’ according to study by world-renowned medical database
February 6, 2023
One of the largest and most comprehensive studies on the effectiveness of masks found they do almost nothing to reduce the spread of respiratory viruses.
The study reviewed 78 randomized control trials—experiments that have long been considered “the gold standard” for medicine—which assessed the effectiveness of face masks against flu, COVID-19, and similar illnesses. It found that wearing masks “probably makes little or no difference” for the general public, no matter what kind of mask is used. Even N95 masks, considered the most effective at filtering airborne particles, showed no clear benefit for health care workers.
The study was published on January 30 by the Cochrane Library, a world-renowned medical database that is famous for its high-quality evidence reviews. It comes as a battering ram to the recommendations of the U.S. public health establishment, which urged children as young as two to wear masks throughout the pandemic.
“This amounts to the scientific nail in the coffin for mask mandates,” said Kristen Walsh, a clinical professor of pediatrics in Morristown, New Jersey. “I just can’t wrap my mind around the fact that some schools are still actively forcing children to wear masks, much less children who need to see faces to learn.”
Though most Western countries opted against masking kids—in part due to concerns about speech and social development—many blue school districts mandated face coverings for toddlers, citing guidance from the Centers for Disease Control and Prevention and the American Academy of Pediatrics.
Both organizations have maintained the masks are effective at curbing COVID-19, including in schools. But the guidance was typically based on weak studies with small sample sizes and few controls, limitations that critics said biased their findings. Many of the studies just compared places with mask mandates with those without them, making it hard to sort out whether it was masks that reduced COVID or other factors, such as that COVID-cautious people were more likely to wear masks.
The sorts of experiments Cochrane canvassed—in which subjects were chosen at random to receive masks—were designed to avoid that problem. They helped researchers isolate the effects of masks from the caution levels of the people wearing them, providing a clearer picture of how well the masks themselves work.
That makes the Cochrane review, which is based exclusively on randomized trials, far more rigorous than the studies typically cited in defense of masks.
“Not all evidence is the same,” Vinay Prasad, an epidemiologist at the University of California, San Francisco, wrote in a Substack post about the review. Randomized control trials “are imperative for recommendations that span years, or longer.”
More than two years after the start of the pandemic, some schools are still requiring masks. School districts in Massachusetts, Michigan, New Jersey, and Pennsylvania reimposed mask mandates in January amid a spike in respiratory illnesses. The mandates came after the CDC warned of a “tridemic” of COVID, flu, and RSV, though cases of all three illnesses have significantly declined.
As of this writing, no major media outlets have covered the Cochrane review. It’s a sharp contrast to the reception of other, more pro-mask studies, which were the subject of glowing write-ups in the New York Times, the Atlantic, and the Washington Post.
The Centers for Disease Control and Prevention did not respond to a request for comment.