It’s long been suspected that the virus that causes Covid-19 could survive in aerosol droplets – tiny particles that linger in the air long after we talk, cough or sneeze – and then infect other people when they breathe them in.
If the virus is living in the air – and potentially travelling distances to infect people – it would be considered “airborne”. This is quite a big deal, as it shifts the measures we use to try and prevent the virus from spreading.
Is Covid-19 airborne?
Airborne transmission is defined by the World Health Organisation (WHO) as the spread of an infectious agent caused by the dissemination of aerosols that remain infectious when suspended in air over long distances and time.
In official circles, SARS-CoV-2 has not yet been confirmed as airborne. However there appears to be growing consensus among some scientists that it is. In July, 239 scientists penned an open letter to WHO warning against underestimating the possibility of airborne transmission.
WHO agrees airborne transmission of the virus can occur during medical procedures that generate aerosols – for example, intubating a Covid-19 patient. But it’s in the process of evaluating whether SARS-CoV-2 may also spread through aerosols in other places, such as indoor settings with poor ventilation. It said the matter of it being airborne “cannot be ruled out”.
Some studies have shown the virus can linger in the air for up to three hours. But one of the major caveats of such studies is that the aerosols are generated using high-powered jet nebulisers under controlled laboratory conditions – this doesn’t reflect normal human cough conditions.
Recently, the US Centers for Disease Control and Prevention (CDC) posted an update on its website acknowledging the virus that causes Covid-19 could be airborne,...