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Masks Protect Wearers, Too, CDC Acknowledges

The agency catches up to what scientists have been saying, adding another reason to mask up

Perhaps people who aren’t willing to don a face covering in the interest of protecting others will be motivated by selfish interests: Masks protect those who wear them from the coronavirus, too, the U.S. Centers for Disease Control and Prevention now says.

It’s a stance leading scientists in the fields of aerosol research and infectious diseases had already concluded, after recent research dispelled the earlier notion that masks were useful mostly just for protecting others from an infected person who wore one.

“Masks are primarily intended to reduce the emission of virus-laden droplets (‘source control’), which is especially relevant for asymptomatic or presymptomatic infected wearers who feel well and may be unaware of their infectiousness to others, and who are estimated to account for more than 50% of transmissions,” the CDC states. “Masks also help reduce inhalation of these droplets by the wearer (‘filtration for personal protection’).”

Well-fitting masks made of the right materials help reduce infectious particles from getting out or in, according to says Linsey Marr, PhD, a scientist at Virginia Tech whose lab studies the effectiveness of various mask types.

“If it fits well with no gaps and you have at least a couple of layers of densely woven material, then it probably protects you against at least half if not 80% or more of the droplets and aerosols that we think are most important for transmission,” Marr has said previously.

Disposable surgical masks are a solid choice, experts say, but their environmental impact makes them an imperfect option for many people. Homemade face coverings and reusable masks can be very effective, too. [See Elemental’s complete guide to choosing, making and wearing masks.]

Masks block large respiratory droplets that tend to fall to the ground quickly, as well as smaller so-called aerosols that can remain airborne for minutes or even hours, building up in poorly ventilated indoor spaces, the CDC now says.

While masks are not perfect, they are one vital layer of protection each individual has some control over, along with avoiding crowds and keeping six feet or more away from people whenever possible, as the pandemic statistics skyrocket out of control.

The new CDC recommendation cites several recent studies revealing the effectiveness of masks against the spread of Covid-19.

“The community benefit of masking for SARS-CoV-2 control is due to the combination of these effects [on the wearer and others],” the agency states. “Individual prevention benefit increases with increasing numbers of people using masks consistently and correctly.”

Independent health and science journalist, former editor-in-chief of LiveScience, writing about how we age and how to optimize your mind and body through time.

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