Federal health officials Wednesday urged Americans to keep their masks on and take steps to make them fit more snugly — or even to layer a cloth covering over a surgical mask — saying that new research had shown that masks greatly reduce the spread of the coronavirus.
Recent laboratory experiments found that viral transmission could be reduced by 96.5% if Americans wore snug surgical masks or a cloth-and-surgical-mask combination. In announcing the findings, Dr. Rochelle P. Walensky, director of the Centers for Disease Control and Prevention, pleaded with Americans to wear a “well-fitting mask.”
“With cases, hospitalizations and deaths still very high, now is not the time to roll back mask requirements,” she said. “The bottom line is this: Masks work, and they work when they have a good fit and are worn correctly.”
Masking is now mandatory on federal property and on domestic and international transportation. Studies conducted in households in Beijing, hair salons in Missouri and aboard an aircraft carrier in Guam have proved that “any mask is better than none,” said Dr. John T. Brooks, the chief medical officer at the CDC and lead author of the agency’s new research on masking.
“Wearing a mask reduces spread, and in communities that adopt mask-wearing, new infections go down,” Brooks said.
But while masks reduce the respiratory droplets and aerosols exhaled by infected wearers, and protect uninfected wearers, air leaking around the edges of a mask can reduce its effectiveness. The agency’s new laboratory experiments showed how to fix the problem.
One option is to wear a cloth mask over a surgical mask, the agency said. The alternative is to fit the surgical mask more tightly on the face by “knotting and tucking” — that is, knotting the two strands of the ear loops together where they attach to the edge of the mask, then folding and flattening the extra fabric at the mask’s edge and tucking it in for a tighter seal.
The agency’s experiments relied on three-ply surgical and cloth masks, and only one type of each mask was tested. Other combinations — like doubling up on cloth masks or wearing two surgical masks, or layering a surgical mask over a cloth mask — were not tested.
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