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The emergence of the quickly spreading COVID-19 Omicron variant has patients wondering what kind of mask they should be wearing, particularly when in public indoor spaces. As knowledge of masks and their benefits continue to evolve, physicians want patients to know what to look for when choosing one to wear.
In April 2020, the first recommendation for mask-wearing was to protect others—your family, friends, and the older adult or immunocompromised person at the grocery store. Now, though, the growing body of evidence suggests that wearing a mask to prevent the spread of SARS-CoV-2—the virus that causes COVID-19—is key to protecting yourself too, according to the Centers for Disease Control and Prevention (CDC).
“The science is really clear on this—masks are an important way that we can all slow down and prevent the spread of COVID-19,” said Preeti Malani, MD, chief health officer and professor of medicine in the infectious diseases division at the University of Michigan. Dr. Malani is also associate editor of JAMA.
It’s essential to practice physical distancing and avoid gatherings, “but basically anytime you’re with anyone not in your immediate household or in any public space when you’ve left your house, we should be wearing a mask,” said Dr. Malani. “It should be part of our uniform, like you would wear shoes.”
“It’s just become something that people have gotten used to. At the same time, there are people who don’t want to wear masks and science is not necessarily guiding that, though,” she said, adding that the science is clear on this—masks are an important tool, along with vaccines, to help stop the spread of COVID-19.
Because SARS-CoV-2 is transmitted predominantly by respiratory droplets and aerosol particles generated when people talk, breathe, sneeze or cough, the CDC recommends community use of masks. With this guidance from the CDC, Dr. Malani offered advice on choosing the right mask to stop the spread of COVID-19.
When choosing a mask, ensure that it fits properly. That means it is snug around the nose and chin without large gaps around the sides of the face.
The mask should be comfortable, said Dr. Malani. “Wear it consistently and make sure it covers your mouth and nose completely.”
Avoid ill-fitting masks such as spandex neck gaiters, which “don’t stay in place for most people,” said Dr. Malani, adding that “gaiters are not lined, which was one of the concerns about them.”
Watch this “AMA COVID-19 Update” episode on what doctors wish patients knew about wearing masks.
With National Institute for Occupational Safety and Health (NIOSH) approved N95 respirators no longer in short supply, CDC guidance provides that people may choose to wear a basic, disposable N95 respirator for personal use instead of a cloth mask in some situations. N95 respirators filter up to 95% of particles in the air when approved by NIOSH and proper fit can be achieved
However, individuals should be aware of the wide range of counterfeit respirators for sale on the market. It is important to be able to identify and select NIOSH-approved N95 respirators vs. counterfeit N95s. People should be aware that about 60 percent of KN95 respirators in the United States are counterfeit and do not meet NIOSH requirements
Given how contagious Omicron is, some experts are encouraging people to upgrade from a cloth mask to an N95 or KF94 when in public indoor spaces. These masks are made of material with an electrostatic charge, which can help prevent a person from inhaling virus particles.
But don’t layer an N95 on top of another mask or respirator, and skip the N95 respirator if you have certain types of facial hair. Additionally, according to the CDC, although respirators may be available in smaller sizes, they are typically designed to be used by adults in workplaces, and therefore have not been tested for broad use in children.
At minimum, people should consider wearing two masks—or double masking—while Omicron and Delta variants continue to spread. This means wearing a cloth mask over a surgical mask for a tighter fit. A mask fitter can also help improve the fit of a person’s mask for better protection.
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 particles emitted during a cough. While double masking or a mask fitter may not offer as much protection as an N95 respirator, they are a big improvement compared to a cloth mask alone.
The use of multilayer cloth masks can block 50–70% of fine droplets and particles. They can also limit the forward spread of droplets and particles that are not captured, notes the CDC. In fact, upwards of 80% blockage has been achieved with cloth masks in some studies, which is about on par with surgical masks as barriers for source control.
Other materials, such as silk masks, may help repel moist droplets. They may also reduce fabric wetting, which can help maintain breathability and comfort for the wearer.
“There was a situation on our campus where people were blowing out candles through the mask that was given to the students and were saying, ‘Well, see this is a bad mask,’” said Dr. Malani. However, “the droplets of viruses are different. Just because you can blow through the mask doesn’t mean it’s not useful.
“But, in general, you want something that is thick enough,” she added.
Some materials can also enhance filtering effectiveness by generating “triboelectric charge,” which is a form of static electricity, says the CDC. This enhances capture of charged particles. While Dr. Malani wears a surgical mask all day at work, she emphasized the need to “change those out every day.”
Medical masks are “disposable—they’re not meant to use over time,” she said. “What I’ll do is I’ll wear an old one in and then I’ll toss it out and put the new one on as they hand it to me.”
Additionally, “if the mask becomes soiled or wet, you should change it out too,” said Dr. Malani.