Surgical masks in large randomized clinical trials do not protect migrants from coronavirus infection, Danish researchers reported Wednesday. But the findings contradict those of many other study experts, and public health recommendations in the United States are unlikely to change, experts said.
Am Bo Amstrap / Ritza Scanpix, Agence France-Presse – by Getty Images
Tram passengers in Aarhus, Denmark. The country needed masks on public transport in transport gust, and only last month in public indoor spaces.
This study, published in Medic Nals Intern f Medicine, does not contradict the growing evidence that wearing a mask virus can transmit to others. But the conclusion contradicts the view that masks also protect wearers – a condition endorsed last week by the Centers for Disease Control and Prevention.
Critics were quick to note the limitations of the study, including that the designer relied heavily on participants reporting his own test results and behavior, at a time when both mask-wearing and infection were rare at the deskmark.
Coronavirus infection is on the rise across the United States, and officials resisting the mask command are also changing. According to a database maintained by The New York Times, about 40 states have implemented certain types of mask requirements.
Anthony Fausi, director of the National Institute of Allergy and Infectious Diseases, advocating for the National Mask Order, advocating for the National Mask Order, As President-elect Joseph R. Biden Jr..
Mr Biden recently wrote on Twitter, “I may not be president until January 20, but my message is for everyone today.
From the beginning of April to the beginning of June, researchers at the University of Copenhagen recruited 6,024 participants who were previously examined to make sure they were not infected with the coronavirus.
Half were given surgical masks and asked to wear them when leaving their home; Others were told not to wear masks in public.
At the time, 2 percent of the Danish population was infected – much lower than this rate in many places in the United States and Europe. Social distance and frequent hand washing were common, but masks were not.
About 4,860 participants completed the study. The researchers hoped that the mask would reduce the infection rate by half. Instead, 42 people in the mask group, or 1.8 percent, became infected, compared to 53 or 2.1 percent in the unmask group. The difference was not statistically significant.
“Our study gives an indication of how much you benefit from wearing a mask,” said Dr. Henning Bundgaard, a study and cardiologist at the University of Copenhagen. “Not a lot.”
Professor Dr. Matte Kalagar, who makes medical decisions at Os Slow University, found the research fascinating. Studies show that “however, there may be no symbolic effect,” he wrote in an email, “the effect of wearing a mask will not reduce the risk”.
Other experts were uncontested. The incidence of infections in Denmark was lower in many places than it is today, which means that it may be difficult for wearers to determine the effectiveness of the mask, they noted.
Participants reported their own test results; The use of masks could not be independently verified, and users may not have worn them properly.
There is no doubt that masks act as resource controls to prevent people from infecting anyone, said Dr. Thomas Frieden, chief executive of the advocacy group Resolve to Save Lives and former director of the CDC. Weaknesses of research.
“The question designed to answer this study is: does it act as personal protection?” The answer depends on what mask is used and what type of virus exposure each person has, Dr. Frieden said, and the study is not designed to get those details out.
“The N95 mask is better than the surgical mask,” said Dr. Frieden. “Surgical masks are better than most cloth masks. A cloth mask is better than nothing. ”
The study’s findings contradict other research suggesting that masks protect the wearer. The CDC cited a dozen studies in its recent bulletin stating that cloth masks can also help protect the wearer. Most of them were laboratory tests of particles blocked by a variety of materials.
Susan Ellenberg, a biostatist at the University of Pennsylvania Pearlman School of Medicine in Medicine, notes that the protection provided by the mask in the test is “in the direction of gain,” even if the results are not statistically significant.
“Nothing in this study suggests to me that wearing a mask is useless,” he said.
Dr. El, a statistician at the Fred Hutchinson Cancer Research Center in Seattle. Elizabeth told Halor that the usefulness of the mask also depends on how many viruses the person is infected with.
“If you show this article to a health care provider who works in a covid ward in a hospital, I doubt they will say that this article guarantees them not to wear a mask,” he said.
But Dr. Christine Lane, editor-in-chief of Internal Medicine, described previous evidence that masks protect people as weak. “These studies cannot distinguish between source control and the personal safety of the mask wearer,” he said.
Dr Lane said the new study emphasized the need to adhere to other precautions, such as social distance. The mask, he said, is “not a magic bullet.” “There are people who say, ‘I’m fine, I’m wearing a mask.’ They need to understand that they are not immune to infection. ”
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