With more contagious coronavirus variants spreading across the U.S. and the supply of COVID-19 vaccines outpacing supply, further guidance has been released about mask-wearing. Maximizing the fit of cloth and medical masks is key to improving performance as well as reducing transmission and exposure of SARS-CoV-2. But wearing two masks—or double masking—can also help protect against the threat of more contagious variants. There’s also new evidence-based advice on outdoor mask-wearing.
“Mask fit is really important because it's about creating an enclosure around any orifice that you could exude the virus particles from through a droplet,” said AMA member Megan Srinivas, MD, MPH, an infectious diseases specialist and translational health policy research fellow at the University of North Carolina at Chapel Hill. “That means covering your nose and mouth completely, but then doing it in a way that it is fitted against your skin.”
Here is what Dr. Srinivas, a delegate for the AMA Resident and Fellow Section, had to say about double masking and other ways to maximize fit and filtration to protect against COVID-19.
Adding more layers of material to a mask or wearing two masks reduces the number of respiratory droplets containing the virus that come through the mask. If one person is using a cloth mask over a surgical mask while the other person is not, it has been shown to block 85.4% of cough particles, says the JAMA Health Forum article, “CDC Studies Underscore Continued Importance of Masks to Prevent Coronavirus Spread.” When both people are double masking, potentially infectious aerosols decrease by 95%.
“By protecting the exterior of the [medical procedure mask] from droplets, you can throw away the outer mask or wash it if it's a cloth mask,” said Dr. Srinivas. “It’s basically the same concept that’s behind when the CDC came out with recommendations saying single-layer masks aren’t as useful as the double layer or masks with filters.”
That is “because it creates more layers of protection for droplets to have to go through to actually be extruded,” said Dr. Srinivas, noting that “when we’re wearing two masks, it creates that extra barrier.”
But “you can’t wear two N95s or surgical masks on top of each other—it wouldn’t be useful,” she said.
Learn more from the CDC on how to improve mask fit for protection.
A cloth mask blocks about 50% of the particles from a simulated cough. But a knotted and tucked mask blocks 77% of those particles, according to the CDC.
To knot and tuck as mask, “pull back and then twist the ear loop behind your ear and knot it, so it makes it a tighter fit,” said Dr. Srinivas. “A lot of the surgical masks people buy are one size fits all, so this way we can make it fit to your face a little bit better.”
The tighter fit helps so that “things can’t seep out in between the crevices and helps to reduce spread to other people,” she said. “It has also helped to reduce your ability to contract from the environment around you, so things can’t sneak in through the crevices around your face.”
Another option is to use a mask fitter or brace over a disposable or cloth mask, “which helps to push your mask against your face for a tighter fit,” said Dr. Srinivas. “The fitter helps to prevent air from leaking around the edges of the mask.”
These mask fitters and braces can be found on Amazon and other retail outlets. They can be solid or elastic and are worn over the mask, secured with head ties or ear loops. When secured over a medical mask, fitters can increase the wearer’s protection by about 90%, according to the CDC.
Many people often forget to wash their cloth masks after use, which is why “a lot of people have moved to disposable masks because it reminds them to get a new one,” said Dr. Srinivas. “You don’t want to repeat using the same cloth mask more than one day in a row without washing it.
“I have a rotation of masks and when I come home, I just toss the one I’ve been using for the day in the laundry basket,” she said. “Then I wash them all at the end of the week.”
“When you start to feel like the seal of the mask is no longer fitting to your face, that's the time when you want to get a new one,” said Dr. Srinivas. “For the general public, just wearing a surgical mask is really sufficient.”
“As far as double masking … once again, it's about the seal,” she said. “If you feel like you're no longer getting the seal, that things are too loose, then toss” the disposable nonsurgical mask “and get a new one to wear underneath your cloth mask.”
The coronavirus variants first identified in the United Kingdom (B.1.1.7), Brazil (P.1) and South Africa (B.1.351) are far more transmissible and lead to higher severity of symptoms, said Dr. Srinivas. The increased transmissibility, not knowing how effective the vaccines are against the variants and “the fact that more variants might pop up as this goes on makes it more important than ever that we continue to mask up.”
“The only way we’re really going to be able to rely on herd immunity is if we can bring the community transmission rates down low enough where the importance of prevention is more important than control,” she said. “With our positivity rates in the United States, we're still in that aspect of—in order to control, we really need masking to be in place.”
“One of the big things that people need to realize is that just because you get vaccinated, you can't stop masking because even though it's reduced the likelihood that you're a carrier, there is still a chance,” said Dr. Srinivas. “We suspect that you can be a carrier for a short amount of time, so you want to protect the community around you.
In April 2021, the CDC updated its advice on mask-wearing. The agency says both fully vaccinated and unvaccinated individuals can safely unmask while:
- Walking, running, hiking or biking outside alone or with members of the same household.
- Attending a small outdoor gathering with fully vaccinated family and friends.
People who are fully vaccinated have additional safe options for outdoor maskless activities. Someone who is fully vaccinated can safely skip the mask while:
- Attending a small outdoor gathering with a mix of fully vaccinated and unvaccinated people.
- Dining at an outdoor restaurant with friends from multiple households.
For these activities, unvaccinated people should continue to wear masks and practice physical distancing, says the CDC. Everyone—vaccinated or not—should also mask up when attending a crowded, outdoor event such as a concert, parade or sporting event.
The CDC guidance indicates that it is still important for everyone, fully vaccinated or not, to wear a mask while inside a public space. That includes going to the movies, attending church, getting on a plane, riding the bus, taking an exercise class at the gym or getting a haircut.
Learn more from the CDC about choosing safer activities during COVID-19.