Covid ‘may linger in air for hours’

‘EMERGING’ evidence shows Covid-19 can spread through tiny particles that linger in the air for hours, the World Health Organisation said yesterday.

It had previously insisted it was primarily spread through large droplets released through coughs and sneezes and which fall to the ground within two metres.

But the agency backtracked after coming under pressure from scientists who believe Covid-19 can be carried by micro-droplets which float in the air and can be inhaled. The WHO yesterday acknowledged the possibility of airborne transmission in ‘crowded, closed, poorly ventilated settings’. This has major implications for guidelines to prevent the spread of coronavirus – as handwashing and social distancing are not effective at cutting airborne transmission.

Unlike droplets, which settle on hard surfaces, microdroplets can linger in the air for hours after being expelled through breath or speech. They can also travel further than two metres, potentially putting pub and restaurant customers at risk.

An infectious disease specialist yesterday said the WHO was waiting to examine the results of studies.

Professor David Heymann, based at the London School of Hygiene and Tropical Medicine, added: ‘ One of these is to put an animal that can be infected into various places around rooms in hospitals or wherever, to see if those animals are being infected, and that’s being done with hamsters.’

The WHO changed its stance after 239 scientists from 39 countries wrote an open letter highlighting potential risks from tiny respiratory particles. It said: ‘ We acknowledge there is emerging evidence in this field.’