Wearing a mask – any mask – reduces the risk of coronavirus infection, but wearing a tight-fitting surgical mask, or putting a cloth mask on top of a surgical mask, can protect the wearer and others. significantly, the Centers for Disease Control and Prevention reported on Wednesday.
New research from the agency shows that transmission of the virus can be reduced by up to 96.5 percent if both an infected person and an uninfected person wear tight-fitting surgical masks or a combination of drape and surgical mask.
Dr. Rochelle P. Walensky, director of the CDC, disclosed the findings at the White House briefing on coronavirus on Wednesday, combining them with a plea for Americans to wear “a well-fitting mask” consisting of two or more layers. . President Biden has challenged Americans to wear masks for the first 100 days of his presidency.
“With hospital admissions and deaths still very high, now is not the time to roll back mask requirements,” she said, adding, “The bottom line is that masks work and they work if they have a good fit and be worn correctly. “
Virus-related deaths, which increased sharply in November in the United States and remain high, appear to be steadily declining; new virus cases and hospitalizations started to decline last month. But researchers warn that a more contagious virus variant first found in Britain is doubling in the United States about every 10 days. The CDC warned last month that it could become the dominant variant in the country by March.
By February 1, 14 states and the District of Columbia had enacted universal masking mandates; masking is now mandatory on federal property and on domestic and international transportation. However, while masks are known to reduce both respiratory drops and aerosols exhaled by infected wearers and to protect the uninfected wearer, their effectiveness varies widely due to air leaks around the edges of the mask.
“Any mask is better than none,” says Dr. John Brooks, lead author of the new CDC study. “There is substantial and compelling data that wearing a mask reduces the spread, and in communities wearing masks, new infections are going down.”
But, he added, the new research shows how protections can be improved. The agency’s new lab experiments are based on the ideas of Linsey Marr, an aerosol transmission expert at Virginia Tech, and Dr. Monica Gandhi, who studies infectious diseases at the University of California, San Francisco.
One option to reduce carryover is to wear a cloth mask over a surgical mask, the agency said. The alternative is to make the surgical mask fit the face more tightly by “tying and tucking” – that is, tying the two strands of the ear loops together where they attach to the edge of the mask, and then the extra fabric to fold and flatten. the edge of the mask and tuck it in for a tighter seal.
Dr. Brooks cautioned that the new study was based on lab experiments, and it’s unclear how these masking recommendations will perform in the real world (the experiments used three-layer surgical masks and cloth masks). “But it’s very clear evidence that the more of us wearing those masks, and the better the mask fits, the more each of us benefits individually.”
Other effective options that improve the fit include using a mask fitter – a frame molded to the face – over a mask, or wearing a sleeve of translucent nylon stockings around the neck and over a cloth or surgical mask, the CDC said. .
Even as vaccines are slowly rolling out across the country, the emergence of the new variants, which may respond differently to treatments or evade the immune system to some extent, has led public health officials to insist that Americans should continue to take protective measures, such as masking.