Almost a year after scientists showed that the coronavirus can be inhaled in tiny droplets called aerosols that linger inside in stagnant air, more than a dozen experts are calling on the Biden administration to take immediate measures to limit aerial transmission of the high-risk virus from places such as meat packing plants and prisons.
The 13 experts – including several who advised President Biden during the transition – have urged the administration to impose a combination of masks and environmental measures, such as better ventilation, to mitigate risks in various workplaces.
The Centers for Disease Control and Prevention issued new guidelines for reopening schools on Friday, but quickly adopted improved ventilation as a precaution. It wasn’t until July that the World Health Organization admitted the virus could linger in the air in crowded indoor spaces, after 239 experts publicly called on the organization to do so.
In a letter to the administration, scientists detailed evidence supporting airborne transmission of the virus. It has become even more urgent for the administration to take action now, experts said, due to the slow rollout of the vaccine, the threat of more contagious variants of the virus already circulating in the United States, and the rate high Covid-19 infections. and deaths, despite a recent decline in cases.
“It’s time to stop snooping on the fact that the virus is transmitted primarily through the air,” said Linsey Marr, an aerosol expert at Virginia Tech.
“If we properly recognize this and put the right recommendations and directions in place, this is our chance to end the pandemic within the next six months,” she added. “If we don’t, it could very well go on forever.”
The letter was delivered Monday to Jeffrey D. Zients, the Biden administration’s Covid-19 response coordinator; Dr Rochelle Walensky, director of the Centers for Disease Control and Prevention; and Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases.
The letter urged the CDC to recommend the use of high-quality masks, such as N95 respirators, to protect workers at high risk of infection. Currently, health workers mainly rely on surgical masks, which are not as effective against aerosol transmission of the virus.
Many workers vulnerable to infection are people of color, who have borne the brunt of the outbreak in the United States, experts noted.
Mr Biden ordered the Occupational Safety and Administration, which sets workplace requirements, to issue emergency temporary standards for Covid-19, including those for ventilation and masks , by March 15.
But OSHA will only prescribe standards backed by CDC guidance, said David Michaels, an epidemiologist at George Washington University and one of the signatories.
(Dr. Michaels led OSHA during the Obama administration; the agency has not had a permanent leader since he left.)
“Until the CDC makes certain changes, OSHA will have a hard time modifying the recommendations it is proposing, as it is understood that the government must be consistent,” said Dr. Michaels. “And the CDC has always been viewed as the lead agency for infectious diseases.”
Public health agencies, including the WHO, have been slow to recognize the importance of aerosols in the spread of the coronavirus. It wasn’t until October that the CDC recognized that the virus could sometimes be airborne, after a confusing sequence of events in which a description of how the virus spreads appeared on the site. Agency web then disappeared, then resurfaced two weeks later.
But the agency’s recommendations on workplace accommodations did not reflect this change.
At the start of the pandemic, the CDC said healthcare workers did not need N95 respirators and could even wear bandanas to protect themselves. He also did not recommend covering their faces for the rest of the population.
The agency has since revised these recommendations. He recently recommended that people wear two masks or improve the fit of their surgical masks to protect themselves from the virus.
“But they don’t say why you need a better-fitting mask,” said Dr. Donald Milton, an aerosol expert at the University of Maryland. “They recognize the importance of inspiring it and the channel of transmission, but they don’t clearly state it in their various web pages.”
The agency recommends surgical masks for healthcare workers and says N95 respirators are only needed during aerosol-generating medical procedures, such as certain types of surgery.
But numerous studies have shown that healthcare workers who do not have direct contact with Covid-19 patients are also at high risk of infection and should wear high-quality respirators, said Dr Celine Gounder, infectious disease specialist at Bellevue Hospital in New York and an advisor to Mr. Biden during the transition.
“The CDC has not emphasized enough the risk of aerosol transmission,” said Dr Gounder. “Unfortunately, concerns about the supply continue to cloud the discussion.”
Many hospitals still expect their staff to reuse N95 masks as per the agency’s recommendation to reuse them when stocks are low. But as masks are no longer scarce, the agency is expected to change its recommendations, Dr Gounder said.
“We really need to stop this approach of reusing and decontaminating N95s,” she added. “We’re a year away and it’s really not acceptable.”
Hospitals, at least, tend to have good ventilation, so healthcare workers are protected in other ways, experts said. But in meat-packing plants, prisons, buses or grocery stores, where workers are exposed to the virus for long periods of time, the CDC does not recommend high-quality respirators and does not endorse ventilation improvements. .
“If you go to other workplaces, this idea that aerosol transmission is important is virtually unheard of,” said Dr. Michaels. In food processing plants, for example, a refrigerated environment and lack of fresh air are ideal conditions for the virus to thrive. But the industry has not put security measures in place to minimize the risk, he added.
Instead, employers follow the CDC’s recommendations for physical distance and surface cleaning.
The recent emergence of more contagious variants makes it urgent for the CDC to tackle the airborne transmission of the virus, said Dr Marr of Virginia Tech. Germany, Austria and France are now mandating N95 respirators or other high-quality masks on public transport and shops.
Dr Marr was one of the experts who wrote to the WHO last summer to call for recognition of airborne transmission. She didn’t expect to be in a similar situation again so many months later, she said, “It’s like Groundhog Day.”