Masking the Problem

Epidemiologist David Larsen explains the science behind public masking recommendations amid the COVID-19 pandemic.

Based on a Syracuse University Story by Rob Enslin originally published on May 8, 2020.

David LarsenDr. David Larsen, a professor in Falk College’s Department of Public Health, studies patterns of sickness and disease in human populations. He is particularly interested in the outbreak of a novel strain of coronavirus because of its personal relevance. “I’ve never worked on a disease system that directly impacts my community,” says Larsen, an expert in malaria research. “I see a lot of parallels between the response to COVID-19 in the United States and to malaria in Zambia.” Experts predict that until an effective vaccine is created and populations develop immunity to COVID-19, stopping or controlling the spread of the disease will be difficult.

Syracuse University’s Rob Enslin recently caught up with Larsen to discuss myths and misconceptions about public masking and why do-it-yourself masks are “better than nothing.”

What kinds of masks are used for COVID-19 protection?

There are three kinds: surgical masks, N95 respirators and cloth masks.

Surgical masks are disposable and loose-fitting, and should be discarded after use. They’re mostly fluid-resistant.

N95 respirators are oval-shaped and form a seal around your face. Because they’re tight-fitting, they filter out about 95 percent of all particles, including viruses and bacteria. It’s important to fit-test a respirator before using or reusing it.

Cloth masks are what most of us wear and should fit snugly against the side of the face. It’s important not to touch your nose, eyes or mouth after removing a cloth mask. It can be washed and reused many times.

The CDC considers surgical masks an “acceptable alternative” to N95 respirators. Do you agree?

It’s confusing, that’s for sure. Research indicates that surgical masks are less protective than N95 respirators. This may explain why front-line health care workers account for 11 percent of all COVID-19 infections. Shortages of N95s and other surgical masks affect the very people who need them most.

Initially, scientists thought COVID-19 was spread by large air droplets, making surgical masks viable. We now know that the virus can be spread by minuscule droplets that hang in the air for up to 16 hours. N95 respirators, if properly fitted, can block most of these air particles. Surgical masks cannot.

What are the public’s options?

I encourage people to make their own masks. They may not be perfect, but they’re better than nothing. I use a pre-quilted cotton fabric. T-shirts, bandanas and denim jeans also work.

There’s been a research breakthrough on the effectiveness of nylon material. Studies show that pantyhose, used in conjunction with a cloth mask, create a tight seal around the wearer’s face. An inner layer of nylon against the skin can match or exceed the filtering capacity of most surgical masks.

Are there any changes in masking guidelines?

The number one rule is to never touch the outside of your mask, only [touch] the straps or ear loops. If you wear glasses, make sure there’s a tight seal above the nose. Otherwise, they fog up.

Viral droplets are emitted from people coughing, sneezing or talking. These particles are very small, less than one-hundredth of a millimeter in size, but are quite resilient. Instead of dropping to the ground, they float or drift in the air before entering someone’s nose or mouth. Having a tight seal is imperative for protection against COVID-19.

Are you suggesting that we practice social distancing in addition to public masking?

I am. It’s not an either/or proposition.

One myth is that we don’t need social distancing if we’re wearing a mask. Masks may reduce transmission, but they’re not completely effective. That’s why we also practice social distancing and hand hygiene.

Many of us may walk through clouds of viral particles without even knowing. As a result, we might not be aware that we’re sick or carrying something. Public masking protects me from you. It shows me that you take my health—and the pandemic—seriously.

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