239 scientists from 32 countries have written an open letter to the World Health Organisation, outlining evidence showing that the novel coronavirus can be transmitted through the air through small particles, Outlook India reported. The scientists have also asked the WHO to revise its guidelines regarding the same.


The WHO has maintained its stance that COVID-19 is primarily spread by large respiratory droplets expelled by infected people through coughs and sneezes that fall on surfaces. So, the WHO’s primary guideline has been to wash our hands as a prevention strategy. 


On the 29th of June, WHO had said that transmission through air was only possible during medical procedures that produce aerosols, or droplets smaller than 5 microns. Such procedures included tracheal intubation, non-invasive ventilation, and tracheotomy among others and as such only healthcare workers were exposed to it. 


Dr Benedetta Allegranzi, the WHO’s technical lead on infection control told reporters: 

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. 

However, experts say that irrespective of large droplets coming from a sneeze or much smaller exhaled droplets that may travel the length of a room, COVID-19 could be spread by inhaling the infected air. 

Mary-Louise McLaws, committee member and epidemiologist at the University of New South Wales in Sydney, Australia says: 

I do get frustrated about the issues of airflow and sizing of particles, absolutely…If we started revisiting airflow, we would have to be prepared to change a lot of what we do.

She also said that if the virus is proved to be airborne, people in closed spaces like offices and malls would be more at risk. And N95 masks would not only be needed by medical professionals but by everyone and stricter social distancing norms would have to be followed.