En español | The Centers for Disease Control and Prevention (CDC) is encouraging all Americans — even people who feel healthy — to wear cloth face masks or homemade face coverings in public when 6-feet social distancing is difficult to maintain in an effort to help slow the spread of the coronavirus. The new guidance, announced Friday, is a reversal from previous CDC recommendations that face masks need to be worn only by people who are sick with COVID-19, the illness caused by the new coronavirus, or by those caring for someone who is sick.
"From recent studies we know that the transmission from individuals without symptoms is playing a more significant role in the spread of the virus than previously understood,” President Donald Trump said in a news briefing Friday. “So in light of these studies, the CDC is advising the use of nonmedical cloth face coverings as an additional voluntary public health measure.”
The masks the CDC is recommending can be purchased online or made at home, said Trump, who stressed that the new recommendations are voluntary. The CDC's website has information on how to make face coverings from everyday household items. Health officials stress that N95 respirator masks and surgical masks should be reserved for frontline health care workers.
Cloth masks do not provide the same level of protection as medical-grade masks, which, if worn properly, can block large and small droplets from coughs and sneezes. But they can offer some germ-blocking benefits, says Joseph Allen, assistant professor of exposure assessment science in the Department of Environmental Health and director of the Healthy Buildings Program at Harvard T.H. Chan School of Public Health.
"It's better than nothing. And that's one of the reasons I think we should be doing this,” Allen said in a recent call with reporters. “Similar to all the other approaches we've been taking, it's an all-in approach. We need to be taking every step we can to minimize disease spread because of the context of what we're facing. It's a pandemic; risk is everywhere, and we're trying to minimize risk everywhere we can.”
Best Face Mask Materials: Cotton With Chiffon
If you are making a homemade mask, a new study published in the scientific journal ACS Nano found that homemade face masks that use a combination of tightly woven cotton and polyester-spandex chiffon or silk will provide a very effective filter for the aerosol particles that spread the COVID-19 virus. Masks made with one layer of cotton and two layers of chiffon (a netlike fabric often found in evening gowns) or silk will filter out some 80 to 99 percent of particles — similar to the effectiveness of the N95 mask material — due to the electrostatic barrier of the fabric. But here’s the kicker: The mask must have a snug fit. Even a 1 percent gap reduces the filtering of all face masks by 50 percent or more.
Some experts argue, however, that masks can provide a false sense of security, leading people who wear them to abandon other important preventive measures. In a recent press briefing, Deborah Birx, a physician and the response coordinator of the White House coronavirus task force, stressed there are other ways people can get infected with the coronavirus, including by touching their eyes, which are not covered by a face mask.
"We don't want — when we're trying to send a signal that every single person in this country needs to stay 6 feet away from everybody, that [people] need to be washing their hands constantly and know where their hands are — to send a signal that we think a mask is equivalent to those pieces,” Birx said.
The CDC says its updated recommendation “complements and does not replace” instructions outlined in the president's coronavirus guidelines, which call on older adults and people with underlying health conditions, in particular, to stay home as much as possible and to avoid others.
It's also important to remember to wash your hands often with soap and water (scrubbing for at least 20 seconds) and to stay home if you are feeling sick, health experts emphasize.
Face masks are “just one more layer of protection,” Allen says. “And the scale and scope of what we're facing, I believe, mandates that we take every precaution we can.”