Fact check: Post about surgical masks’ effectiveness against COVID-19 is missing context – USA TODAY

The claim: Surgical masks don’t prevent respiratory viruses from clinging to air particles and circulating

For almost two years, masking up has been a fundamental part of America’s COVID-19 prevention tactics. But a post on social media claims the type of mask that many wear to prevent the spread of the virus is ineffective. 

“I’m a surgeon. Surgical-style masks keep droplets containing bacteria from falling from one’s nose or mouth onto a surgical field. They do that,” a Dec. 30, 2021, Instagram post reads. “They DON’T prevent RESPIRATORY viruses from clinging to tiny particles and circulating into the air. Stop the madness!”

The post is a screenshot of a tweet by Dr. Nan Hayworth, a former New York representative, commenting on airline mask mandate policies. It received more than 13,000 retweets and 32,200 likes.

The claim gets some of the facts right. Surgical masks are primarily intended to block large droplets. However, experts say surgical masks still provide some protection from airborne viruses, which is better than none in the context of the COVID-19 pandemic.

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“If I’m riding in a car that only has a lap belt rather than one with a shoulder harness, the lap belt is still better than nothing,” said Dr. Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who studies viruses in the air. 

The Instagram user, another medical doctor, said in response to USA TODAY’S request for comment that he thinks masking negatively affects children and called it a “form of child abuse.”

Surgical masks offer some protection against COVID-19

Hayworth told USA TODAY surgical masks, particularly on airline flights, are “not protective,” because of those masks’ inability to fully block the virus. 

“No one who chooses to mask in any form should be criticized or ridiculed. But mandates are both ineffectual and burdensome,” she said. “A mandate to wear N95 masks could be effective, assuming full compliance – an enormous ‘if’, but it would be exceedingly burdensome, and most people do not need that level of protection, nor should it be forced on them.” 

Marr told USA TODAY in an email that, “by the book,” surgical masks are considered ineffective as personal protection. But in the context of a global pandemic, the partial protection provided by surgical masks helps prevent spread.

“Surgical masks are made of the same, or very similar, type of material as used in N95s, so the material in a surgical mask is quite capable of filtering out small particles, such as viruses in respiratory aerosols,” Marr said. “Their weakness is that they are loose-fitting and do not seal to the face, so things can leak in and out of the gaps around the sides.

She said masks provide at least partial protection by reducing the amount of virus that is released by the wearer and reducing the amount breathed in from the surrounding air.

“Partial protection is still useful because the more virus we inhale, the more likely we are to become infected, Marr said.” 

More:Most people are still wearing cloth masks. Here’s why that’s a problem with omicron

Research conducted throughout the pandemic confirms this. A September 2021 study published in Oxford Academic’s Clinical Infectious Diseases journal found that surgical masks reduce viral shedding in aerosols from COVID-19 patients by 48% to 77%. Another study, published in the American Society for Microbiology Journals in October 2020, determined surgical masks reduce the amount of COVID-19 inhaled by the mask-wearer by about 50%.

Both the Centers for Disease Control and Prevention and the Food and Drug Administration acknowledge on their websites that surgical masks are generally meant to help protect against large droplets, splashes or sprays of possibly germy fluid. Both agencies also say that the masks should be used by the general public and health care personnel to help reduce spread.

“(The poster’s) claim that surgical masks are primarily designed to protect the operative field from bacteria is correct,” Dr. Michael Klompas, a hospital epidemiologist at Brigham and Woman’s Hospital and professor of population medicine at Harvard Medical School, said in an email. “In terms of viruses and aerosols, (the poster is) only partly correct. (Surgical masks) provide partial protection against viral transmission. As such they lower the chances of transmission but they do not eliminate it.”

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Hayworth agreed that masks “may thwart – not entirely block” a virus from spreading via cough or sneeze. 

Wearing face coverings additionally prevents spread by protecting others from the wearer, the CDC and experts note.

Post misrepresents how respiratory viruses travel

Marr additionally said the post’s claim that surgical masks “don’t prevent respiratory viruses from clinging to tiny particles and circulating into the air” misrepresents how respiratory viruses behave in the air.

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“The viruses are released as part of tiny respiratory particles (aerosols) when we breathe, talking, sing, and cough and do not need to take the additional step of ‘clinging’ to anything,” she said. These respiratory aerosols are a mixture of water, salts, proteins, other components of respiratory fluid, and potentially viruses if the person is infected. Viruses are not released naked into the air.”

Which mask provides the most protection against COVID-19?

In a September 2020 study published in the journal Science Advances, researchers tested 14 different masks to see which stood up best against COVID-19 droplet transmission.

Among the masks tested were the fitted N95 mask, surgical mask, valved N95 mask, knitted mask, neck gaiter, bandana and a number of cotton and polypropylene masks. The control variable was no mask.

More:Federal mask mandate to be extended: Be prepared to mask up on planes through mid-March

The study determined that the fitted N95 mask is the best option for keeping out COVID-19, followed by the surgical mask. The worst option – ranked below wearing no mask – is the neck gaiter, according to the study.

Cotton masks primarily ranked in the middle of the pack, with the best cotton option being a polypropylene-cotton blend and the worst being a two-layer cotton, pleated style mask. The bandana and knitted mask ranked third and fourth to last, before the no-mask control. 

Previous studies have found that any protection is better than none. 

A 2013 study in the journal Disaster Medicine and Public Health Preparedness examined homemade masks compared to commercial face masks. Researchers found that both commercial masks and homemade masks provided protection, but the surgical masks were three times more effective in blocking transmission.

Fact check:The COVID-19 pandemic is not a hoax

“Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection,” the study reads.

Our rating: Missing context

Based on our research, we rate the claim that surgical masks don’t prevent respiratory viruses from clinging to air particles and circulating as MISSING CONTEXT because without additional information it could be misleading. Surgical masks are primarily intended to block large droplets. However, experts say they still provide some protection, which is better than none in the context of the COVID-19 pandemic.

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