Speaking to someone when infected with COVID-19 could be as dangerous as coughing near them due to tiny droplets known as aerosol particles, new research has shown.
COVID-19 can be spread via a number of routes, but research has shown that transmission is most common from aerosol droplets emitted when an infected person breaths, speaks or coughs.
This heightened transmission route, experts say, could help explain why the virus spreads more easily indoors or when there is poor ventilation.
Large droplets fall and do not pose a large risk of transmission, but aerosols can carry the virus over distances greater than 2 meters and remain for longer.
Experts at Cambridge University have conducted studies to assess the risk of COVID-19 spread from large droplets and aerosols.
Their results suggest that it takes just a couple of seconds for expelled particles to travel beyond 2 meters, posing significant challenges for mitigating this risk of transmission.
“You need masks, you need distancing and you need good ventilation so these particles don’t build up in an indoor space and they’re safely removed,” said Prof. Pedro Magalhaes de Oliveira, an expert in fluid mechanics at Cambridge University and the study’s co-author.
The team concluded that it is unsafe to stand without a mask 2 meters away from an infected person who is talking or coughing, with both situations posing a heightened infection risk.
This risk is especially high in unventilated spaces, such as indoor settings with closed windows.
The team said the total amount of COVID-19 aerosol that is spread from 30 seconds of speaking is higher than just one cough, and it remains for up to an hour.
The team added that in small spaces and without ventilation, this might be enough to cause COVID-19.