{"id":614657,"date":"2023-03-05T08:49:04","date_gmt":"2023-03-05T14:49:04","guid":{"rendered":"https:\/\/news.sellorbuyhomefast.com\/index.php\/2023\/03\/05\/do-masks-work-its-a-question-of-physics-biology-and-behavior\/"},"modified":"2023-03-05T08:49:04","modified_gmt":"2023-03-05T14:49:04","slug":"do-masks-work-its-a-question-of-physics-biology-and-behavior","status":"publish","type":"post","link":"https:\/\/newsycanuse.com\/index.php\/2023\/03\/05\/do-masks-work-its-a-question-of-physics-biology-and-behavior\/","title":{"rendered":"Do masks work? It\u2019s a question of physics, biology, and behavior"},"content":{"rendered":"
\n
\n

\n There are no easy answers \u2014
\n<\/h4>\n

A recent review from a prominent scientific source has reignited the debate over masks.<\/h2>\n
\n

\n Michael Schulson, Undark<\/span><\/a>
\n –

\n
\n
\n \"Asian
\n

Enlarge<\/a> \/<\/span> Asian woman with protective face mask using smartphone while commuting in the urban bridge in city against crowd of people<\/p>\n<\/figcaption><\/figure>\n

On March 28, 2020, as COVID-19 cases began to shut down public life in much of the United States, then-Surgeon General Jerome Adams issued an advisory<\/a> on Twitter: The general public should not wear masks. \u201cThere is scant or conflicting evidence they benefit individual wearers in a meaningful way,\u201d he wrote.<\/p>\n

Adams\u2019 advice was in line with messages from other US officials and the World Health Organization<\/a>. Days later, though, US public health leaders shifted course. Mask-wearing was soon a pandemic-control strategy worldwide, but whether this strategy succeeded is now a matter of heated debate\u2014particularly after a major new analysis, released in January, seemed to conclude that masks remain an unproven strategy for curbing transmission of COVID-19 and other respiratory viruses.<\/p>\n

\u201cThere\u2019s still no evidence that masks are effective during a pandemic,\u201d the study\u2019s lead author, physician, and epidemiologist Tom Jefferson, recently told<\/a> an interviewer.<\/p>\n

Many public health experts vigorously disagree with that claim, but the study has caught attention, in part, because of its pedigree: It was published by Cochrane<\/a>, a not-for-profit that aims to bring rigorous scientific evidence more squarely into the practice of medicine. The group\u2019s highly regarded systematic reviews affect clinical practice worldwide. \u201cIt\u2019s really our gold standard for evidence-based medicine,\u201d said Jeanne Noble, a physician and associate professor of emergency medicine at the University of California, San Francisco. One epidemiologist described Cochrane as \u201cthe Bible.\u201d<\/p>\n

The new review<\/a>, \u201cPhysical interventions to interrupt or reduce the spread of respiratory viruses,\u201d is an updated version of a paper published<\/a> in the fall of 2020. It dropped at a time when debates over COVID-19 are still simmering among scientists, politicians, and the broader public.<\/p>\n

For some, the Cochrane review provided vindication. \u201cMask mandates were a bust,\u201d conservative columnist Bret Stephens wrote<\/a> in The New York Times last week. \u201cThose skeptics who were furiously mocked as cranks and occasionally censored as \u2018misinformers\u2019 for opposing mandates were right.\u201d<\/p>\n

Meanwhile, masks continue to be recommended by the US Centers for Disease Control and Prevention, which describes<\/a> them as \u201ca critical public health tool.\u201d And this winter, some school districts<\/a> issued short-term mandates in an effort to curb not just COVID-19, but other respiratory viruses, including influenza and RSV.<\/p>\n

The polarized debate conceals a murkier picture. Whether or not masks \u201cwork\u201d is a multilayered question\u2014one involving a mix of physics, infectious disease biology, and human behavior. Many scientists and physicians say the Cochrane review\u2019s findings were, in a strict sense, correct: High-quality studies known as randomized controlled trials, or RCTs, don\u2019t typically show much benefit for mask wearers.<\/p>\n

But whether that means masks don\u2019t<\/em> work is a tougher question\u2014one that has revealed sharp divisions among public health researchers.<\/p>\n

The principle behind masks is straightforward: If viruses like SAR-CoV-2 or influenza can spread when droplets or larger particles travel from one person\u2019s nose and mouth into another person\u2019s nose and mouth, then putting up a barrier may slow the spread. And there\u2019s certainly evidence that surgical masks can block some relatively large respiratory droplets.<\/p>\n

Early in the pandemic, though, some researchers saw evidence that SARS-CoV-2 was spreading via tinier particles, which can linger<\/a> in the air and better slip around or through surgical and cloth masks. \u201cSweeping mask recommendations\u2014as many have proposed\u2014will not reduce SARS-CoV-2 transmission,\u201d respiratory protection experts Lisa Brosseau and Margaret Sietsema wrote<\/a> in an April 2020 article for the Center for Infectious Disease Research and Policy at the University of Minnesota.<\/p>\n

Their colleague Michael Osterholm, a prominent epidemiologist, was more blunt: \u201cNever before in my 45-year career have I seen such a far-reaching public recommendation issued by any governmental agency without a single source of data or information to support it,\u201d he said on a podcast<\/a> that June. (The Minnesota center receives funding from 3M, which manufactures both surgical masks and respirators.)<\/p>\n

In a recent interview with Undark, Brosseau stressed that she thinks cloth and surgical masks have some<\/em> protective benefit. But she and others, including Osterholm, have urged policymakers to emphasize tight-fitting respirators like N95s, rather than looser-fitting cloth and surgical masks. That’s because there\u2019s clear evidence that respirators can effectively ensnare those tiny particles. \u201cA well-fitting, good quality respirator will trap the virus, almost all of it, and will greatly reduce your exposure to it,\u201d said Linsey Marr, an engineering professor at Virginia Tech who studies the airborne transmission of viruses.<\/p>\n<\/p><\/div>\n