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Covid-19 variants ‘getting better’ at transmission through air, study finds

People infected with the Alpha variant were, in particular, found to exhale ‘43 to 100 times’ more virus than those infected with the original strains.
Pedestrians, some wearing face coverings due to Covid-19, walk past shops on Oxford Street in central London on June 7, 2021. (Used for representative purpose only_
Published on Sep 21, 2021 02:57 PM IST
By hindustantimes.com, New Delhi

A study conducted by researchers at the University of Maryland has found that variants of SARS-CoV-2, which causes the coronavirus disease (Covid-19), are evolving to “get better” at transmission through air, news agency PTI reported. The report, which was published in the journal Clinical Infectious Diseases, also found that people who contract this viral illness through the Alpha variant of SARS-CoV-2, exhale “43 to 100 times” more virus into the air than those infected with its original strains.

Sharing thoughts on the study, doctoral student Jianyu Lai, one of its lead authors said, “We already knew that the virus in saliva and nasal swabs was higher in infections caused by the Alpha variant. Virus from the nose and mouth might get transmitted by large droplets up close to an infected person. However, we found that the virus in exhaled aerosols is rising further,” Lai said.

These major increases in airborne virus due to Alpha, researchers said, took place when the Delta variant was yet to be discovered. This, according to them, indicates that the variants are “getting better” at transmitting through air.

Meanwhile, Don Milton, a professor at the University of Maryland School of Health, said that the research provides further evidence of the importance of airborne transmission. “We know that Delta is more contagious than Alpha. Our research indicates that the variants just keep getting better at travelling through the air. Therefore, in addition to vaccination, we must provide better ventilation and wear tight-fitting masks to help stop it from spreading,” Milton explained.


To check the efficacy of face masks, the team measured how much SARS-CoV-2 is breathed into air, and then tested how much less virus is exhaled by Covid-19 patients after putting on a cloth or surgical mask.

While face masks were found to have significantly reduced, by around 50 per cent, virus-laden particles in the air around the Covid-19 patient, loose-fitting cloth and surgical masks failed at preventing infectious droplets from going out.


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