Cloth masks offer limited protection as omicron spreads, experts warn

WASHINGTON (TND) — Public health experts are increasingly urging Americans to set aside the cloth masks many have become accustomed to wearing during the COVID-19 pandemic and strap on heavier, more protective medical-grade face coverings to slow the spread of the omicron variant.

New infections in the U.S. have hit record levels as the highly transmissible mutation circulates. Vaccines and boosters appear to be preventing severe symptoms for many, but the sheer number of cases still threatens to overwhelm hospital systems.

“Certainly, wearing a mask, and more importantly a better mask, has never been this urgent -- due to the sheer contagiousness of the variant and its ability to be suspended in aerosols for some time – especially in indoor spaces with poor ventilation,” said Graham McKeen, assistant director of public and environmental health at Indiana University.

Cloth masks with varying layers have been widely available since the spring of 2020, but they are not as effective as disposable surgical masks. N95 respirators, which filter out nearly all airborne particles and are commonly used in health care settings, are typically made with polypropylene. KN95, KF94, and FFP2 masks are made from similar material, but they do not necessarily meet the standards of U.S. regulators.

“They are made with a special material that is very efficient at filtering out particles of all sizes, and they are designed to seal to your face to minimize leakage that could short circuit the filtering material. They are also designed to be easy to breathe through,” Linsey Marr, a researcher at Virginia Tech who studies how viruses travel in the air, said of respirator masks, though she added, “Some are more comfortable than others.”

Many KN95 masks sold in the U.S. are counterfeit, but experts say one purchased from a reliable vendor should provide comparable protection to an N95. Wider use of such devices could make a difference in the weeks ahead as the omicron variant spreads.

“Not all face masks are created equal. N95 face masks are far more effective than cloth masks in preventing the spread of COVID,” Sen. Bernie Sanders, I-Vt., said on Twitter Sunday, urging the federal government to step up production and distribute medical-grade masks to every household in the U.S.

Some medical experts have offered similar advice. In an article in the Journal of the American Medical Association last week outlining a proposed new national strategy for combating COVID-19, former Biden transition adviser Dr. Ezekiel Emanuel and other experts pushed for a national initiative to provide free or low-cost N95 or KN95 masks to all Americans.

“The country needs to encourage use of high-quality filtering facepiece respirators (FFRs), such as N95s or KN95s, rather than cloth or surgical masks, to reduce transmission of respiratory viruses including SARS-CoV-2 in crowded indoor settings where community exposure risk is elevated,” they wrote.

In California, where an indoor mask mandate is in effect through mid-February, the Department of Public Health recommends surgical masks or higher-level respirators, but it does not require them. The University of Arizona updated its guidance last week to mandate surgical masks or high-grade face covering in indoor spaces.

“Please note that cloth masks will no longer meet the face covering requirement,” the Jan. 5 guidance states.

Federal officials were slow to advocate widespread masking in the early days of the pandemic, partly due to limited supplies. As they learned more about how COVID-19 spreads, face coverings became a central element of the nation’s virus response, but agencies have stopped short of calling for everyone to wear N95s or similar devices.

In defending its recent decision to shorten recommended quarantine times for those who test positive for COVID-19 to five days, the Centers for Disease Control and Prevention emphasized the importance of wearing “a well-fitted mask” when one leaves isolation. However, the agency has not changed its guidance to promote higher quality masks.

That has spurred some concern from experts who fear the thin and sometimes poor-fitting cloth masks many have been wearing for the last 20 months offer insufficient defense against the threat of this variant.

“Cloth masks aren't going to provide a lot of protection, that's the bottom line,” Dr. Scott Gottlieb, former head of the Food and Drug Administration, told CBS News last week. “This is an airborne illness. We now understand that, and a cloth mask is not going to protect you from a virus that spreads through airborne transmission.”

Others do not completely dismiss the value of a cloth mask, particularly if one uses a brace to tighten it or wears a surgical mask beneath it.

“It’s still true that any mask is better than no mask, yet there is huge variability in the effectiveness of different kinds of masks,” Marr said. “While a simple cloth mask might provide 20% protection, a high-performance mask can achieve 90% protection or better.”

Delineating the real-world effectiveness of a specific COVID-19 mitigation measure independent of others can be difficult, but a review of available research published in the British Medical Journal in November estimated a 53% reduction in infection associated with mask-wearing. Some communities that had mask mandates were also found to have significantly lower mortality and transmission rates than those that did not.

"The biggest jump in protection is from no mask to any mask," Dr. Allison Arwady, commissioner of the Chicago Department of Public Health, said in a Facebook video last week, adding that she does not feel a need to wear a KN95 regularly.

The CDC points to nearly two dozen studies affirming that face coverings can significantly reduce the risk of COVID-19 infection. However, much of that research did not compare different types of masks, and most of the studies were conducted before the more infectious delta and omicron variants emerged.

One study published last month in the American Journal of Infection Control estimated cloth masks were two to four times less effective than medical masks, with filtration efficiency of 20% to 36%. A 4-ply cloth mask with a mask brace offered comparable protection to unmodified medical masks, though.

“The performance of face masks as devices that control infection spread depends upon both the ability of the mask material to filter aerosols and on how well the mask fits the wearer,” said lead author Francoise Blachere, a research biologist at the National Institute for Occupational Safety and Health.

A large-scale study of rural villages in Bangladesh by researchers at Stanford Medicine and Yale University found people living in areas where residents were provided free surgical masks were 11% less likely to contract COVID-19 than those without masks. Villages with cloth masks saw fewer cases than those that were maskless, but the difference was not deemed statistically significant.

According to the American Conference of Governmental Industrial Hygienists, an uninfected person can catch COVID-19 from an infected person in 15 minutes if neither is wearing a mask. That time nearly doubles if both are wearing cloth masks and quadruples if both wear surgical masks. A person wearing an N95 mask can be protected for 25 hours or more, regardless of what others wear.

The World Health Organization refers to well-fitting cloth masks as “an acceptable option, when other options are not available,” but it recommends that those who are at high risk or who believe they might have contracted the virus wear medical masks. Some experts would go further in light of the latest surge of infections.

“My advice would be, get rid of the cloth mask, get rid of the gaiter,” Dr. Stephen Thomas, director of global health at Upstate Medical University told CNY Central recently, describing cloth masks as little more than a “decoration” that only reduces risk by about 10%.

The CDC does not dispute that KN95s and N95s work much better, but it has not backed off its support for more ubiquitous cloth masks. Dr. Rochelle Walensky, the agency’s director, has expressed concerns people might opt not to cover their faces at all if they are expected to wear the less comfortable medical masks.

“If people want extra layers of protection, the KN95 or N95s do offer that,” Walensky told PBS NewsHour. “But what I also want to really emphasize is that you need to be able to keep them on when you're in those settings. Those KN95 and N95s are often not as comfortable. So, if you're going to take it off, the really important thing to do is make sure you're masking the entire time.”

McKeen said comfort is a valid consideration because any mask becomes much less useful if one frequently needs to adjust or remove it. However, given the heightened threat of omicron, he advised upgrading from a cloth mask to ensure better protection.

“They are better than nothing, and again will work better when everyone else is masked, but are less effective than surgical masks, which are less effective than KN95s/KF94s/FFP2s, and N-95s, and so on. I’d urge us all to wear better masks over the next several weeks,” he said.

Despite the increased risk of infection and rising hospitalizations, many federal, state, and local officials have been reluctant to impose new restrictions on the public as they struggle to contain the omicron variant. They stress the availability of effective vaccines and treatments, and they acknowledge people who are not adhering to current guidance are unlikely to comply with more onerous new rules.

“I’m not sure the people that are refusing to wear a mask are going to wear one anyway, and we don’t have the ability to enforce it," Maryland Gov. Larry Hogan said last week. "So, we’re just strongly encouraging people to wear the damn mask.”

That encouragement might not be enough, and the masking debate has grown highly partisan and politicized as the pandemic drags on. Still, experts say the public would be best served by formal guidance that makes clear which face coverings work best, even if that means revising what officials have said in the past.

“I think many of us are fatigued and jaded with the pandemic, but now is not the time to let our guard down...,” McKeen said. “We should at least let folks know that there are better options to protect themselves and others against a highly contagious and airborne virus. As the virus and the science evolves, we should too.”