Virus infections predominantly by air: Lancet

Deccan Chronicle.  | Balu Pulipaka

Science

Aerosol particles do not need a ‘carrier’, such as a droplet, for the virus to ride on

Their findings shows that anywhere from 33 to 59 per cent of all Covid-19 transmissions in the world were not related to people coughing or sneezing. (Photo: AFP)

Hyderabad: Making the worst fears about how Covid-19 spreads and how the disease-causing SARS-CoV-2 travels from one person to another, a study published by Lancet, the venerated medical journal, has said that the virus spreads “predominantly by the airborne route.”

In their study, published by Lancet on April 15, researchers from the US, Canada and the United Kingdom, said there was enough evidence to surmise that the SARS-CoV-2 spreads through the aerosol route. Ever since the pandemic broke out early last year, the predominant view has been that Covid-19 spreads only through droplets – microscopic liquid particles emitted by an infected person while coughing, sneezing or talking with virus taking a ride in those particles – that are inhaled by another person.

The study comes just two days after the Telangna state Director of Health Dr G. Srinivasa Rao, in the wake of the severe surge in Covid-19 cases, warned of the dangerous situation and said it was no longer a stretch to say that the virus is now airborne.

In their study published by Lancet, six experts from the three countries provided 10 reasons why they believe that the virus is airborne and spreads as an aerosol particle. Aerosol particles do not need a ‘carrier’, such as a droplet, for the virus to ride on.

The paper ‘Ten scientific reasons in support of airborne transmission of SARS-CoV-2’ said one of their findings was that Covid-19 infections in hospitals have been documented even at places where healthcare professionals used personal protective equipment designed to protect against droplet but not aerosol exposure.

They said there is an urgent need for safety protocol modifications as one of their findings shows that anywhere from 33 to 59 per cent of all Covid-19 transmissions in the world were not related to people coughing or sneezing. “Direct measurements show that speaking produces thousands of aerosol particles and few large droplets, which supports the airborne route,” view, they said.

They also said that the dominant rate of infections occurring indoors than outdoors, and how transmission rates can be cut with good ventilation, supports the argument that Covid-19 spreads “predominantly” by the airborne route.

While saying that it is likely that the disease spreads through droplets, the researchers said “there is consistent, strong evidence that SARS-CoV-2 spreads by airborne transmission. Although other routes can contribute, we believe that the airborne route is likely to be dominant. The public health community should act accordingly and without further delay.”

The study can be accessed here: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00869-2/fulltext

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