Weeks after the one-year official anniversary of the COVID-19 novel coronavirus pandemic, the CDC introduced new guidelines on Wednesday recommending those in the US make sure their face mask fits snugly and has multiple layers. In some cases, a second face mask may be advised.
"Make sure your mask fits snugly against your face. Gaps can let air with respiratory droplets leak in and out around the edges of the mask," the updated guidance details. "Pick a mask with layers to keep your respiratory droplets in and others’ out. A mask with layers will stop more respiratory droplets getting inside your mask or escaping from your mask if you are sick."
The CDC release emphasized that one should only layer up by wearing a "cloth mask that has multiple layers of fabric" or by donning "one disposable mask underneath a cloth mask."
"The second mask should push the edges of the inner mask against your face," the federal health agency advises.
According to the CDC, one should not "combine two disposable masks," as they are "not designed to fit tightly and wearing more than one will not improve fit." Furthermore, one should not combine a KN95 mask with any other mask.
Health officials, like Dr. Stuart Cohen, a chief of infectious diseases and director of hospital epidemiology and infection control at UC Davis, also point out that some cloth masks can be enhanced by a "particulate filter."
“There are some cloth masks that have a filter you can put in a pouch. That’s functionally double-masking. So there are some masks that are, by themselves, acceptable,” Cohen told Rolling Stone earlier this week. “Double-masking is a way of trying to turn your regular mask into more of an N95-type situation—where it’s tighter, where you’ve added an extra layer, where the virus droplets have to do a lot more dancing to get through," the health professional added. "So it protects both you and the people that you’re with.”
The CDC has also published findings from two recent studies that highlight "the importance of good fit to maximize mask performance" and "more effectively slow the spread of COVID-19."
"CDC conducted experiments to assess two ways of improving the fit of medical procedure masks: fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face," researchers detailed in the February 10 release. "Each modification substantially improved source control and reduced wearer exposure."
"The data in this report underscore the finding that good fit can increase overall mask efficiency," researchers wrote. "Multiple simple ways to improve fit have been demonstrated to be effective."
The report concluded by highlighting that "continued innovative efforts to improve the fit of cloth and medical procedure masks to enhance their performance merit attention."