Almost a year after scientists showed that the coronavirus can be inhaled in tiny droplets called aerosols that linger in stagnant indoor air, more than a dozen experts are calling on the Biden government to take immediate action to stop the transmission of the virus in the air at high risk limit settings such as meat packing plants and prisons.

The 13 experts – including several who advised President Biden during the transition – urged the administration to mandate a combination of masks and environmental measures such as better ventilation to mitigate the risks in various workplaces.

On Friday, the Centers for Disease Control and Prevention issued new guidelines for reopening schools, but quickly switched to improved ventilation as a precaution. It was only in July that the World Health Organization admitted that the virus could linger in the air in overcrowded indoor spaces after 239 experts publicly urged the organization to do so.

In a letter to the administration, scientists explained detailed evidence of airborne transmission of the virus. It has become even more urgent that the government take action now, the experts said due to the slow vaccine rollout, the threat of more contagious variants of the virus already circulating in the US and the high infection and death rate. despite a recent drop in cases.

“It’s time to stop pussy shooting because the virus is mostly airborne,” said Linsey Marr, aerosol expert at Virginia Tech.

“If we properly acknowledge this and implement the right recommendations and guidance, this is our chance to end the pandemic in the next six months,” she added. “If we don’t do that, it could very well drag on.”

The letter was delivered to Jeffrey D. Zients, Coordinator of the Biden Administration’s Covid-19 Response, on Monday. Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention; and Dr. Anthony S. Fauci, Director of the National Institute for Allergies 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. At present, health care workers rely mostly on surgical masks, which are not as effective against aerosol transmission of the virus.

Many workers susceptible to infection are black people who have borne the brunt of the epidemic in the United States, the experts noted.

Mr Biden has directed the occupational health and safety agency, which sets workplace requirements, to issue temporary emergency standards for Covid-19 by March 15, including those for ventilation and masks.

However, OSHA will only prescribe standards that are supported by the CDC, said David Michaels, an epidemiologist at George Washington University and one of the signatories.

(Dr. Michaels ran OSHA during the Obama administration; the agency has not had a permanent leader since his departure.)

Updated

Apr. 17, 2021, 10:34 p.m. ET

“Until the CDC makes some changes, OSHA will have difficulty changing the recommendations as it understands that government must be consistent,” said Dr. Michaels. “And CDC has always been considered the lead infectious disease agency.”

In a statement emailed, CDC officials stressed the proper use of wipes and surgical masks to protect against the virus, saying that N95 respirators are not recommended for the general public “for reasons prompted by science, comfort, Cost and practicality are supported “.

Public health authorities, 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 realized that the virus could be in the air at times, after an enigmatic series of events where a description of how the virus had spread appeared on the agency’s website, then disappeared, and reappeared two weeks later.

However, the Agency’s recommendations on workplace accommodation did not reflect this change.

At the start of the pandemic, the CDC said health care workers didn’t need N95 respirators and could even wear headscarves to protect themselves. Face coverings were also not recommended for the rest of the population.

The agency has since revised these recommendations. It was recently recommended that you wear two masks or improve the fit of their surgical masks to protect yourself from the virus.

“But they’re not talking about why you need a better fitting mask,” said Dr. Donald Milton, aerosol expert at the University of Maryland. “They recognize the importance of inhaling it and how it is transmitted, yet they don’t say it clearly on their various web pages.”

The agency recommends surgical masks for health care workers and says that N95 respirators are only needed during medical procedures that generate aerosols, such as certain types of surgery.

However, many studies have shown that health care workers who have no direct contact with Covid-19 patients are also at high risk of infection and should wear good quality respirators, said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center in New York and an advisor to Mr. Biden during the transition.

“The CDC has not emphasized the risk of aerosol transmission enough,” said Dr. Gounder. “Unfortunately, concerns about the offer continue to cloud the discussion.”

Many hospitals still expect their staff to reuse N95 masks as recommended by the agency to reuse when supplies are low. However, since the masks are no longer in short supply, the agency should change its recommendations, said Dr. Gounder.

“We really need to stop this approach of reusing and decontaminating N95,” she added. “We are one year this year and that is really not acceptable.”

At least hospitals are usually well ventilated, so healthcare workers are protected in other ways, the experts said. In meat packers, prisons, buses, or grocery stores where workers have been exposed to the virus for long periods of time, the CDC does not recommend high-quality respiratory equipment or advocate improvements to ventilation.

“When you go to other jobs, that notion that aerosol transfer is important is virtually unknown,” said Dr. Michaels. For example, in food processing plants, a refrigerated environment and lack of fresh air are ideal conditions for the virus to thrive. However, the industry has not taken any safety measures to minimize the risk, he added.

Instead, employers follow the CDC’s recommendations for physical removal and cleaning of surfaces.

The recent emergence of more contagious variants makes it imperative for the CDC to address airborne transmission of the virus, said Dr. Marr from Virginia Tech. Germany, Austria and France are now mandating N95 respirators or other high quality masks in public transport and shops.

Dr. Marr was one of the experts who wrote to WHO last summer asking for airborne transmission recognition. She didn’t expect to be in a similar position again so many months later. She said, “It feels like Groundhog Day.”