A recent research has suggested that speaking to a friend when infected with the virus could be just as dangerous as coughing close to them, thanks to lingering particles.
Droplets containing the virus are typically spread when an infected person speaks, breathes and coughs. Large droplets eventually fall to the ground over short distances, but tiny droplets called aerosols are able to carry the virus over distances greater than two meters.
Experts have now developed models to investigate the risk posed by large droplets and aerosols and look for ways to mitigate it. Their findings indicate that it takes only a few seconds for expelled particles to travel beyond two meters.
According to Prof Pedro Magalhães de Oliveira, an expert in fluid mechanics at the University of Cambridge and co-author of the study, “You need masks, you need distancing, and you need good ventilation, so these particles don’t build up in an indoor space, and they are safely removed.”
The research team also took infection risk into account, considering the viral load of people infected with the virus and the estimated dose required to cause an infection, using samples derived from studies of a different coronavirus for the latter.
They concluded that it was unsafe to stand two meters away from an infected person who is talking or coughing, especially when you’re not wearing a mask. Both situations pose an equal infection risk.
“Speaking is a very important issue that has to be considered because it produces much finer particles [than coughing] and these particles, or aerosol, can be suspended for over an hour in amounts that are sufficient to cause the disease,” said de Oliveira.
However, the chances of people catching COVID-19 is dependent on how much of the aerosol they breathe in, which in turn is influenced by other factors such as whether a mask is worn, levels of ventilation and the distance between the people involved.