Watch your back: Chinese study finds Covid-19 could be on your tail

Researchers in China say virus particles can land on the clothes of someone passing a seated infected person within four seconds

Peer-reviewed paper suggests the virus can ride the turbulence created by the body’s movements to approach from behind

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Tsinghua University researchers say the best strategy to reduce the risk of air transmission is to “stay put” rather than move through the area. Photo: EPA-EFE

Published: 8:00am, 16 Apr 2022

Chinese scientists say they have discovered an unexpected pathway to infection from Covid-19 – with more than 80 per cent of the tiny floating particles of virus on the breath landing on the back and buttocks of a passer-by.

Until now, the highest risk of exposure was commonly believed to be the nose, mouth and eyes.

But Weng Wenguo and his colleagues at Tsinghua University’s engineering physics department suggest the virus can also approach from behind, by riding on the wake of turbulence produced by the body’s movements.

What’s more, it can jump on to a moving person in a surprisingly brief period of time, according to the team’s paper published last month in the peer-reviewed Journal of Tsinghua University (Science and Technology).

When sharing a room with possibly infected people, the best strategy to reduce the risk of air transmission was not to run through them, but to “stay put”, they said.

According to the researchers, the reason is that virus-carrying aerosols can build up near a seated infected person. The wake turbulence caused by someone walking past can draw the infected particles towards the rear of the passer-by.