The New York Times first reported Saturday that an international coalition of researchers will publish an open letter asking WHO to address airborne transmission of the virus. The scientists say there is growing evidence tiny aerosols can linger in the air indoors and result in new infections.
Throughout the pandemic, WHO has maintained that the virus spreads mainly through larger respiratory droplets or contact and has primarily urged people to wash their hands and socially-distance to prevent infection. These droplets, released by coughs or sneezes, are heavier than smaller aerosols and fall to the floor more quickly, thus presenting less of a threat if proper distance is maintained between a healthy and infected person.
However, if airborne transmission of the coronavirus is a significant threat, it could dramatically impact safety guidelines. According to the Times, people would need to wear masks inside places with poor ventilation even if they were socially distancing. Ventilation systems in schools and businesses would need to be updated to use powerful new filtration. Health care workers would also require high-quality N95 masks to filter out even the smallest droplets.
The scientists’ letter, titled “It Is Time to Address Airborne Transmission of COVID-19,” will be published this week in the journal Clinical Infectious Diseases.
Don Milton, a co-author of the letter and a professor at the University of Maryland, said on Twitter that the group was calling on WHO to revise guidelines in light of the possible aerosol threat.
“Simple things can make a big difference,” Milton wrote. “Wear masks whenever you are not at home; even simple homemade masks can have a major impact. Open windows. Don’t gather in large groups inside with singing and loud talking. These three simple things will save lives.”
Even as states reel from a resurgence in cases, scientists still don’t know how many people have been infected, why some patients show symptoms for months and others none at all, and how close to a vaccine the world may be or how well it will work.
Dr Benedetta Allegranzi, WHO’s technical lead on infection control, said she remained unconvinced that airborne transmission was a threat.
“Especially in the last couple of months, we have been stating several times that we consider airborne transmission as possible but certainly not supported by solid or even clear evidence,” Allegranzi told The Times. “There is a strong debate on this.”