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Face masks can protect wearers as well as others from contracting the coronavirus, according to new guidance issued Tuesday by the CDC.
The update shifts previous guidance that said face masks mainly prevent you from spreading the virus to others, rather than protecting you from others.
"Masks also help reduce inhalation of [respiratory] droplets by the wearer," the CDC wrote.
Multi-layered cloth masks can provide "filtration for personal protection" and block virus particles exhaled by others, according to the new update. The scientific brief cites several recent studies that have shown a reduction in virus transmission — by more than 70% in some cases.
In one example, mask use among both parties prevented transmission from two infected hair stylists to their 67 clients who were later monitored for infection. In another scenario, people who wore face masks on long international flights avoided infection from fellow travelers.
"Adopting universal masking policies can help avert future lockdowns, especially if combined with other non-pharmaceutical interventions such as social distancing, hand hygiene, and adequate ventilation," the CDC wrote.
The coronavirus spreads through respiratory droplets, particularly when people cough, sneeze, sing, talk or breathe. Certain types of cloth masks may be nearly as effective as surgical masks at blocking these respiratory droplets, according to the updated guidance. Polypropylene may create a static charge that captures particles, for instance, and silk may repel droplets.
Overall, masks with multiple layers and high thread counts are more effective at stopping transmission than single-layer masks with lower thread counts. In some cases, multi-layer masks filtered nearly 50% of fine particles that were smaller than 1 micron, the CDC wrote.
Wearing face masks is a "two-way street," Anthony Fauci, MD, the director of the National Institute for Allergy and Infectious Diseases, told MSNBC on Tuesday.
"Recent data has now shown that, as a matter of fact, there's also the added benefit to protect you from droplets and virus that's coming your way," he said. "You protect others, their mask protects you, and your mask also protects you."
CDC, "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2."
NBC News, "‘Two-way street': CDC report says masks protect wearers and everyone else."
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Cite this: Masks Protect Wearers Along With Others, New CDC Guidance Says - Medscape - Nov 12, 2020.