A scientist, who was one of 239 signatories of a letter to the World Health Organization over concerns Covid-19 could be an airborne virus, has called on the UN health body to update its guidance.
The WHO has previously said the virus spreads primarily through small droplets expelled from the nose and mouth of an infected person that quickly sink to the ground.
But in an open letter to the Geneva-based agency, published on Monday in the Clinical Infectious Diseases journal, 239 scientists in 32 countries outlined evidence that they say shows floating virus particles can infect people who breathe them in.
When an infected person exhales, they expel droplets. Droplets under five micrometres in size can become suspended in the air for several