The scientist serving as the technical lead for the World Health Organization’s coronavirus response said on Friday that droplets and contact are still the “dominant” roots of COVID-19 transmission after the group allowed this week that airborne particles indoors could spread the disease.”
There may be other modes of transmission which we don’t rule out,” Maria Van Kerkhove said at a briefing. “Aerosol transmission is one of the modes of transmission that we have been concerned about since the beginning, particularly in health care settings.”
In those settings, she said, they recommend health care workers take special precautions with protective equipment.
“Outside of health care settings, there is the possibility that there could be aerosolized particles in specific settings like indoor settings where there are crowded conditions, where there’s poor ventilation, and where people are spending prolonged periods of time,” she said.
She said more research into the issue is warranted.
On Thursday, the WHO issued a new brief acknowledging that the coronavirus can spread via airborne transmission indoors, after previously emphasizing that droplets people forcefully expel through sneezing or coughing are prime spreaders.
“It’s not a guidance document — it’s a brief,” Ms. Van Kerkhove said. “This is a living review, which means it will be updated regularly.”
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Friday at an AIDS conference that there is “still some question” about aerosol-based transmission but that there is “likely some degree of aerosol.”
More than 200 scientists had recently written an open letter calling for national and international groups to recognize the potential for airborne spread of COVID-19.
The WHO has been under fire for its response to the pandemic in recent weeks and months.
The group is in the midst of sending a team to China, where the virus was first discovered late last year, as it investigates the origins of the outbreak.
President Trump notified the United Nations and Congress this week that the United States was withdrawing from the WHO, though the exit wouldn’t take effect until July 2021.
Mr. Trump and others have said the health group was too eager to accept China’s narrative about the origin and scope of the virus.