While COVID-19 vaccines and booster shots are highly effective, they’re not always enough to prevent infection, especially with the omicron variant. Northwestern faculty discuss the importance of universal masking — and deciding which type to wear — as well as the ways one can maximize effectiveness, enable reusability and obtain higher-quality masks.

Masking distinction and specifics

Cloth and surgical masks are loosely fitting barriers between the nose, mouth and environment. While cheaper and reusable, cloth masks don’t provide adequate filtration, putting the user at risk for inhaling viral particles.

When worn properly, surgical masks can contain large respiratory droplets but are not as effective in filtering particles that come from coughing or sneezing. They’re intended to be single use and should be replaced immediately if damaged or stained.

Respirator masks like the N95, KN95, FFP2 and KF94 provide a tight seal around the nose and mouth and filter airborne particles from the immediate surrounding environment. They’re rated based on the percentage and size of air particles they’re able to filter out.

Notable differences across these respirators exist in filter performance and design, with N95s having bands that wrap around the head and the others having loops — some adjustable — around the ear. Feinberg Prof. Richard D’Aquila said N95s provide the best protection out of the four international equivalents.

Feinberg Prof. Alexis Demonbreun said respirators can potentially be worn for up to two weeks, and wearing multiple masks on a rotation can prevent moisture buildup. Surgical masks, on the other hand, can be unusable after a few hours of wear.

Demonbreun said wearing a cloth mask on its own won’t provide much protection, and surgical masks run the risk of letting air through the sides due to their loose fit. However, surgical masks can be effective if worn properly, Demonbreun said, and individuals can even layer them with cloth masks on top.

“Just about any mask is better than nothing, but the more people that wear (KN95) or N95 masks, the better, especially if you’re in a close indoor social setting with not good ventilation,” biological anthropologist and anthropology Prof. Thomas McDade said.

Masking substantially decreases risk of infection, according to a study in the Proceedings of the National Academy of Sciences. It found that individuals who were unmasked and distanced about 10 feet apart had a 90% risk of infection if one of them had the virus. If the uninfected individual wore a surgical mask, they reached a 90% risk of infection after 30 minutes of interaction at a distance of five feet.

When both individuals are wearing a surgical mask, the risk is below 30% even after an hour. But when those masks are N95-type respirators, the risk becomes 0.4%.

“The real secret to masking and how it protects us best is universal masking,” D’Aquila said. “When two people are masked, that gives you double protection.”

Mask fitting

McDade said the best masks are those that provide a good seal over the nose and a tight fit around the mouth.

According to Demonbreun, methods of ensuring a tighter fit include tying a knot with the loops around the ear or using bobby pins to fasten the mask more tightly around the face.

There are also other signs that indicate a mask isn’t well fitted.

“For people who wear glasses, if you go out in cold weather and your glasses fog up (quickly), you’ve got some leaks probably around your nose or around the top of your cheeks,” D’Aquila said. “Facial hair will prevent (the mask) from being a tight fit … It always makes me a little nervous when I see people with those big bushy beards wearing a mask — it’s some help, but not much.”

When and where to mask

Masking both indoors and outdoors when there’s a possibility of exchanging viral particles is important, especially with the omicron variant, McDade said.

Demonbreun said the minimum type of mask to wear depends on the location and the situation. While low-ventilated and crowded places where social distancing can’t be maintained would warrant wearing a respirator, Demonbreun said surgical masks may suffice in other environments.

“If you were in a grocery store at seven in the morning and you’re the only person there, a surgical mask would be just fine,” Demonbreun said. “If you were in an office setting and your desks are spaced six feet apart, a surgical mask is definitely suitable for those types of environments.”

She added that immunocompromised individuals should wear KN95s or N95s wherever they go.

Obtaining masks

Surgical masks are available at building entrances throughout campus.

A Residential Services email sent to some students Thursday indicated undergraduates living on-campus can pick up a pack of two KN95 masks at their Area Desks. Residents living in Engelhart Hall or McManus Center will find KN95s in their mailboxes, and individuals living in Garrett Place can pick up masks from the Engelhart Desk.

According to a Wednesday Return to Campus Discussion Series webinar, faculty and staff will receive information on KN95s specifically available for them.

Masks are also available with online sellers such as Amazon, D’Aquila said, though individuals who buy masks online should be aware of counterfeits when it comes to KN95s.

“You have to look up a listing that the FDA has to look for which manufacturer (and) which brand is under an EUA and actually filters the way it’s supposed to,” D’Aquila said.

Campus policies on masking

While it’s recommended to wear high-quality masks in shared campus environments, students will be required to wear a surgical mask, at minimum, once in-person classes resume Jan. 18.

Instructors are encouraged to wear masks while lecturing, with the exception of “extreme distancing” measures, such as at the front of a large lecture hall.

“The reason to wear a mask in public is that you can’t always control that the other person is masked,” D’Aquila said. “That’s actually one of the layered protections we have at the University because we have this requirement that everyone wear masks.”

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