On March 28, 2020, as COVID-19 cases began to block public life across much of the United States, then-Surgeon General Jerome Adams said: Recommendation on Twitter: “People should not wear masks. “Evidence that they benefit individual wearers in a meaningful way is scant or conflicting,” he writes.
Adams’ advice was consistent with messages from other US officials and the World Health Organization. But days later, US public health leaders changed course. Wearing a mask has quickly become a global pandemic control strategy, but the success of this strategy remains to be seen, especially in a major new analysis released in January that masks are effective in curbing transmission of COVID. After seemingly concluding that it was an unproven strategy, it is now hotly debated. -19 and other respiratory viruses.
“There is still no evidence that masks are effective during a pandemic,” the study’s lead author, physician and epidemiologist Tom Jefferson, recently told an interviewer.
Although many public health experts vehemently disagree with that claim, one of the reasons this study has attracted attention is because of its pedigree. medicine. The group’s acclaimed systematic reviews influence clinical practice around the world. Gene Noble, an internist and associate professor of emergency medicine at the University of California, San Francisco, said: One epidemiologist described Cochrane as “the Bible.”
A new review, “Physical Interventions to Prevent or Reduce the Spread of Respiratory Viruses,” is an update of a paper published in the fall of 2020. He was removed at a time when the debate over COVID-19 was still boiling among scientists and politicians. , and the wider public.
For some, Cochrane reviews provided corroboration. Conservative columnist Brett Stevens wrote in The New York Times last week that “mask mandates have failed.” “The skeptics who were furiously ridiculed as freaks and occasionally censored as ‘misinformation’ for opposing orders were right.
Meanwhile, the U.S. Centers for Disease Control and Prevention continues to recommend masks as an “important public health tool.” And this winter, some school districts issued short-term orders to curb not only COVID-19, but other respiratory viruses, including influenza and RSV.
The polarizing debate hides a darker picture. Whether masks “work” is a multi-layered question, intricately intertwined with physics, infectious disease biology, and human behavior. Many scientists and doctors say the Cochrane review findings are technically correct. High-quality studies, known as randomized controlled trials (RCTs), typically do not show many benefits for mask wearers.
But if that means masks please do not The task is a tougher question, revealing sharp disagreements among public health researchers.
The principle behind masks is simple and straightforward. Install barriers where viruses, such as SAR-CoV-2 or influenza, can be spread by droplets or large particles traveling from one person’s nose or mouth to another’s nose or mouth can slow the spread. There is also some evidence that surgical masks can block relatively large respiratory droplets.
However, early in the pandemic, some researchers found evidence that SARS-CoV-2 spread through smaller particles. Particles remain in the air and can slip through or through surgical and cloth masks. In an April 2020 article for the Center for Infectious Diseases Research and Policy at the University of Minnesota, respiratory protection experts Lisa Brosseau and Margaret Sietsema said, “As many have suggested, sweep mask recommendations are not for SARS. -does not reduce CoV-2 transmission.”
Their colleague, eminent epidemiologist Michael Osterholm, was more outspoken. He said in a podcast that June, (The Minnesota center is funded by his 3M, which makes both surgical masks and ventilators.)
In a recent interview with Undark, Brosseau said cloth and surgical masks Several protective interest. But she and others, including Osterholm, have urged policymakers to emphasize tight-fitting respirators like the N95 rather than loose cloths and surgical masks. That’s because there’s clear evidence that ventilators can effectively trap these tiny particles. A well-fitting, high-quality respirator can trap almost all viruses and significantly reduce your exposure to the virus.
