The World Health Organisation (WHO) is reviewing a report suggesting that Covid-19 can spread through tiny airborne particles, media reports indicate.

According to the health agency’s guidelines, the novel coronavirus can spread through small droplets from the nose or mouth, which are expelled when an infected person coughs or sneezes or speaks.

However, over 239 scientists in 32 countries have written an open letter to the Geneva-based health agency, outlining evidence that people can get infected by smaller particles of the virus in the air, the New York Times reported.

"We are aware of the article and are reviewing its contents with our technical experts," WHO spokesman Tarik Jasarevic said, as quoted by a Reuters report.

According to the scientists, much smaller exhaled droplets carrying the virus that can travel in any part of a room can infect people when inhaled.

However, the WHO had initially said that airborne transmission is not supported by solid evidence.

“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,” Benedetta Allegranzi, the WHO's technical lead of infection prevention and control, was quoted as saying by the NYT report.

According to Reuters, if proven, the WHO will require to change its guidelines. Any change in the guidelines could also affect the agency’s assessment of the risk of transmission as well as its public advisories including keeping 1 metre of physical distancing. It could also affect policy guidelines by governments including social distancing norms.

The WHO is yet to consider if the findings warrant such change in guidelines, the report said.

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