A new study has shown that the airborne transmission of COVID-19 is highly random and suggests that the two-metre rule was a number chosen from a risk ‘continuum’, rather than any concrete measurement of safety.

A team of engineers from the University of Cambridge used computer modelling to quantify how droplets spread when people cough. They found that in the absence of masks, a person with COVID-19 can infect another person at a two-metre distance, even when outdoors.

The team also found that individual coughs vary widely, and that the ‘safe’ distance could have been set at anywhere between one to three or more metres, depending on the risk tolerance of a given public health authority.

The results, published in the journal Physics of Fluids, suggest that social distancing is not an effective mitigation measure on its own, and underline the continued importance of vaccination, ventilation and masks as we head into the winter months in the northern hemisphere.

Despite the focus on hand-washing and surface cleaning in the early days of the pandemic, it’s been clear for nearly two years that COVID-19 spreads through airborne transmission. Infected people can spread the virus through coughing, speaking or even breathing, when they expel larger droplets that eventually settle or smaller aerosols that may float in the air.

«I remember hearing lots about how COVID-19 was spreading via door handles in early 2020, and I thought to myself if that were the case, then the virus must leave an infected person and land on the surface or disperse in the air through fluid mechanical processes,» said Professor Epaminondas Mastorakos from Cambridge’s Department of Engineering, who led the research.

Story Source: Materials provided by University of Cambridge. The original text of this story is licensed under a Creative Commons License. Note: Content may be edited for style and length.