Cloth masks have become a staple of the pandemic, but as for their effectiveness against the new omicron variant, they may be more fashion than function. Amid surging COVID-19 cases driven by the highly transmissible strain, many public health experts are now recommending medical-grade masks or layering cloth masks for better protection.
“Because omicron is more contagious, it requires less time and less exposure for infection,” Dr. Abraar Karan, an infectious disease physician at Stanford University, said in an interview. “That's why upgrading your mask is so critical right now.”
As omicron spreads, some hospitals, health care systems and universities around the country are starting to require higher quality masks. Duke University Health System in North Carolina, the Mayo Clinic in Minnesota and Arizona State University are among those discouraging or outright banning cloth masks in favor of hospital-grade ones for students, patients and visitors. In several European countries, medical-grade masks are mandatory in public places.
The Washington Post reported Monday that the Centers for Disease Control and Prevention is considering updating its mask guidance to recommend N95 or KN95 masks, according to an official close to the deliberations who was not authorized to speak publicly.
“The agency is currently actively looking to update its recommendations for KN95 and N95 in light of omicron,” the official said, according to The Post. “We know these masks provide better filtration.”
COVID-19 is transmitted through respiratory droplets and tiny particles called aerosols that get released into the air by an infected person. The longer you spend with an infected person and the more droplets and particles you breathe in, the more likely you are to become infected. Poor ventilation makes it even more likely that you’ll get infected.
Masks reduce the spread of COVID-19 when an infected person exhales and also protect the wearer when they inhale. But not all masks are equal. While single-layer cloth masks can block larger droplets, they’re not as good at filtering out smaller particles which can linger in the air longer.
“The better quality the mask is, the more protective it is,” Dr. Debra Bogen, director of the Allegheny County Health Department, said during a Jan. 5 briefing.
At the beginning of the pandemic, medical-grade masks and other personal protective equipment were only recommended for health care workers, not the general public, because they were in short supply. But as our understanding of how the virus spreads has grown and the availability of these masks has increased, experts now say it’s a good idea to get these masks if you can.
How do I know if my current mask is good enough?
“If you can feel your breath hit you in the eyes or around your mouth when you breathe,” it’s time to up your mask game, Dr. Matthew Moffa, medical director of infection prevention at AHN West Penn Hospital, said in an interview. “Think about all the airborne particles that can escape your mask and that you can also breathe in.”
Dr. Moffa said a snug-fitting, multi-layered mask will provide the best protection against the omicron variant.
What type of mask should I buy?
By now you’re probably familiar with surgical masks. Maybe you’ve heard of N95s and KN95s. Let’s break down how they differ.
Surgical masks — typically blue on the outside — are made with soft, permeable material and have ear loops. They’re looser-fitting on the face, meaning leakage occurs around the edge of the mask when the wearer breathes in and out.
N95 respirators are made of tough yet flexible material and are tested and regulated by the National Institute for Occupational Safety and Health, or NIOSH. N95s are designed to have a very close fit and form a seal around the mouth by strapping around the back of the head.
KN95s, meanwhile, are similar to N95s but are certified by the Chinese government and don’t fit quite as tightly. Like surgical masks, KN95s have straps that loop around the ears. Both N95s and KN95s are ideal in crowded indoor settings with poor ventilation when not everybody around you is masking. “They really enhance your own personal protection,” Dr. Moffa said.
Surgical masks, N95s and their equivalent are all made of multiple layers of non-woven polypropylene, a material with an electrostatic charge that allows it to trap particles. The difference is in the fit of the mask, how they’re certified and the amount of particles they can filter out.
How effective are the different types of masks?
“The material and type of mask are important considerations for the amount of aerosols at different size ranges that they can filter out,” said Seema Lakdawala, an associate professor of microbiology and molecular genetics at the University of Pittsburgh School of Medicine.
“A well-fitted mask that is made of multiple layers of tight woven material worn around their nose and mouth is a good place to start,” she said.
A randomized study of more than 350,000 individuals carried out in rural Bangladesh in 2020 found that people were 9% less likely to develop COVID-19 when around 42% of villagers wore cloth masks. When surgical masks were introduced, people were 11% less likely to get sick. The findings were published in December in the journal Science.
Other studies have shown that multi-layer cloth masks can block between 50% to 70% of large droplets and smaller particles when they’re worn snug to the face. N95s and KN95s get their name because they filter out at least 95% of all airborne particles, including large droplets and much smaller particles. Surgical masks can filter out larger particles but not smaller ones.
Can I reuse medical-grade masks?
The short answer is yes. But the experts we talked to said how often you replace them will depend on how long you wear them and in what settings. You can rotate them out just like cloth masks, but you can’t wash surgical masks or N95 respirators.
You should throw away masks if they get wet, soiled or stretched or when they can no longer stay on your face. Discard any masks with holes or torn straps. You should store your masks in a place where they won’t get wet or be exposed to direct sunlight. Ultraviolet light can degrade N95s and KN95s over time.
Where can I find better quality masks?
For high-filtration masks, you’ll likely have to shop online, although some retailers like Lowe’s and Home Depot carry N95 respirators. Well-known brands include 3M, Honeywell and Kimberly-Clark. The CDC has a list of NIOSH-approved N95 respirators and ProjectN95.org provides links on where to purchase them.
KN95s are widely available on Amazon, but the CDC has warned that about 60% of KN95 respirators available in the United States are counterfeit and don’t meet NIOSH standards. It can be difficult to spot counterfeits, but the Food and Drug Administration has published a list of models that are no longer authorized to help consumers navigate purchasing these masks.
Are there any alternatives?
N95 respirators can feel harder to breathe through than a cloth mask, so those with chronic respiratory, cardiac, or other medical conditions should check with their health care provider before using one.
Others may find N95s or KN95s uncomfortable or ill-fitting. If you can’t find a model you like, you can layer a cloth mask over a surgical mask to better lock in that seal. Many cloth masks also have pockets for non-woven polypropylene filters, which boost protection. It may take some trial and error to figure out what’s most comfortable for you.
“Any mask is better than no mask, and that's really the message,” Dr. Bogen said, “but the mask does have to be worn properly.”
Emily Mullin: emullin@post-gazette.com
First Published: January 11, 2022, 10:59 p.m.
