Experts Express Concern Over Airborne Spread of More Contagious Coronavirus

Prevention efforts must be increased before mutant strains cause a resurgence

Illustration: mathisworks/Getty

With more contagious and perhaps deadlier strains of the coronavirus circulating, the Biden administration should forcefully acknowledge that airborne spread is a primary means of transmission, then take immediate action to strengthen measures to reduce risk, especially in schools and workplaces, according to a letter signed by 13 leading scientists and physicians with expertise in infectious diseases, aerosol transmission, and occupational health. The letter was sent to U.S. officials leading the pandemic response.

“It will be months before most of the population is vaccinated,” the letter states. “In the meantime, more transmissible variants are projected to become the dominant strains by March and may pose significant challenges to the efficacy of first-generation vaccines and monoclonal antibodies,” which are among the most effective Covid-19 treatments. “While Covid-19 infections and deaths have started to decline in recent weeks, they remain at a very high level and, unless strengthened precautionary measures are implemented, the new variants will likely bring an explosion in new infections.”

The letter was addressed to Rochelle Walensky, MD, director of the U.S. Centers for Disease Control and Prevention; Jeffrey Zients, coordinator of the president’s Covid-19 pandemic response; and Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases.

“The federal government and CDC must clearly acknowledge that inhalation of aerosols, produced simply by speaking, is a major factor leading to the spread of Covid-19,” one of the signatories, Kimberly Prather, PhD, told the Coronavirus Blog via email. Prather is director of the Center for Aerosol Impacts on Chemistry of the Environment in the Scripps Institution of Oceanography at the University of California, San Diego.

“Once this is acknowledged, clear guidance for effective controls, such as improved filtration and ventilation, can be provided to protect high-risk workers and the public while safely reopening schools and businesses,” Prather says. “The federal government also needs to increase the supply of masks so everyone can be better protected, especially against the more transmissible new variants.”

Yes, it’s definitely airborne

Infectious disease experts have for months urged federal and state health officials and policymakers to better communicate the need for effective masks and improved building ventilation and air filtration as key layers of Covid-19 prevention, particularly in schools and other crowded buildings.

Science has shown convincingly that the coronavirus is airborne.

“CDC guidelines and recommendations are out of date and do not fully recognize inhalation exposure or include the necessary control measures to protect the public or workers from this mode of transmission,” the letter states.

“The virus spreads mainly by breathing in virus that is in aerosols,” signatory Linsey Marr, PhD, a scientist at Virginia Tech and an expert on the transmission of the coronavirus through the air, told the Coronavirus Blog in an email. “These are microscopic droplets that can easily travel farther than six feet and fill a room.”

The letter writers commend the Biden administration for already instituting mask mandates on federal property and issuing stronger measures to safeguard workers. But the lack of federal and state coordination to staunch the spread of Covid-19 over the past year has created an ever more urgent need for additional action to prevent further large-scale deaths and economic displacement, which has been particularly devastating to people of color and others working frontline and essential jobs.

What the Biden administration should do

The recommendations in the letter include:

  • Strengthen CDC guidelines to fully address transmission via inhalation.
  • Provide proper respiratory protection for all health care workers, whether on the front lines of Covid-19 or otherwise, and everyone with prolonged, close contact with infectious people.
  • Issue new workplace prevention rules through the Occupational Safety and Health Administration, including high-performing masks even for lower-risk employees, adhering to ASTM standards that call for at least 80% filter efficiency and lack of leaks around the edges.
  • Update CDC recommendations for masks used by the public.
  • Use the Defense Production Act to help fund and coordinate production and distribution of N95 respirators and other types of masks known to be highly effective.

“There isn’t one magic bullet,” Marr says. “But if I had to pick something that is doable and would have the most effect, it would be for CDC to recommend that people wear a mask adhering to the new ASTM standards, covering their noses and mouths, at all times when indoors with others (beyond their own household).”

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.

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