US: In an open letter to the World Health Organization, 239 scientists from 32 countries have claimed that the Covid-19 coronavirus is airborne, The New York Times reported on Saturday. The scientists plan to publish their findings in a journal this week.
The claim contradicts previous evidence that suggested that it was transmitted from person to person through droplets from the nose or mouth, which are expelled when a person with the disease coughs, sneezes or speaks.
WHO has so far emphasised that the virus can spread through the air only in case of medical procedures that produce aerosols, or droplets smaller than five microns. The global health body has instead promoted frequent hand washing as a means to keep the virus away, though the probability of the contagion spreading through surfaces is very low.
But Dr Benedetta Allegranzi, WHO’s technical lead on infection control, said the evidence that coronavirus is airborne is unconvincing. “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,” she said. “There is a strong debate on this.”
In April, a group of 36 experts on air quality and aerosols had urged WHO to consider growing evidence on airborne transmission of the virus. The health body called Lidia Morawska, the group’s leader and a WHO consultant, for a meeting. However, at the meeting, WHO experts continued to stress the importance of hand washing, and felt it should be emphasised over aerosols, The New York Times reported.
At the meeting, Morawska provided evidence of several incidents that indicate airborne transmission of the virus, contending that the WHO was making an artificial distinction between tiny aerosols and larger droplets, though infected individuals produce both.