Scientists say that handwashing and social distancing alone will not prevent spread of the disease.
The World Health Organization (WHO) is reviewing a report that suggested its advice on the novel coronavirus needs updating, after scientists wrote an open letter saying there was evidence the virus could be spread by tiny particles in the air.
The WHO says Covid-19 spreads primarily through small droplets, which are expelled from the nose and mouth when an infected person breaths them out in coughs, sneezes, speech or laughter and quickly sink to the ground.
In an open letter published in the journal Clinical Infectious Diseases, 239 scientists in 32 countries outlined the evidence they say shows that smaller exhaled particles can infect people who inhale them, the newspaper said on Saturday.
Because those smaller particles can linger in the air longer, the scientists are urging WHO to update its guidance.