Spread of 'eminently' possible coronavirus by speech, experiment finds

Text by: RFI Follow

According to an experiment published on May 13 in the scientific journal PNAS, the new coronavirus is likely to be transmitted by speech alone. The cause: the microdroplets of saliva, generated by it. In an enclosed space, they can stay in the air for more than 10 minutes.

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The new SARS-CoV-2 coronavirus, responsible for Covid-19 disease, a global pandemic and a serious health and economic crisis , has not yet revealed all its secrets. But research is progressing, and while laboratories are working on treatments and a possible vaccine , a study published Wednesday May 13 in the scientific journal Proceedings of the National Academy of Sciences ( PNAS ) brings new data on this virus, and more particularly on its spread.

Microdroplets suspended for several minutes

It was already known that coughing and sneezing promote the transmission of the coronavirus via the expulsion of microdroplets. Hence these recommendations for wearing masks and social distancing. But it turns out that these invisible microdroplets can also be projected when speaking.

This is the conclusion of an experiment conducted by researchers from the National Institute of Diabetes and Digestive and Kidney Diseases. They made a person speak in a closed box. This person had to repeat, with both strong and for 25 seconds, the words "  Stay healthy  " ( "  Be well  ").

Result: Scientists, using a laser, determined that the microdroplets stayed in the air for an average of 12 minutes. Their conclusion: the loud speech of an infected person can generate the equivalent of more than 1,000 contaminated droplets per minute. And these droplets can stay suspended in the air for 8 minutes or more, in a closed space.

In a plea for face masks, researchers visualize how speech sends fluid droplets flying. In PNAS Journal Club: https://t.co/1OO5w9fymL # COVID19Pandemic # COVID19 #SocialDistancing #Social_Distancing pic.twitter.com/KTrDUBLToi

Wearing masks more than ever recommended

In April, work published by the same scientists in The New England Journal of Medicine already indicated that speaking louder produced relatively fewer droplets. Their last experience tends to confirm their first observation. At the beginning of April, the American National Academy of Sciences also warned against these droplets projected by coughing, sneezing and speech.

The scientifically proven infectiousness of the new coronavirus by speech is an additional argument for health authorities regarding the usefulness of wearing masks. It is also a factor explaining a little more the Covid-19 pandemic, which, as of May 14, 2020, nearly 300,000 dead and infected more than 4,362,000 people worldwide.

(With AFP)

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