Covid is evolving “to spread better in the air”

The coronavirus is evolving to spread better in the air, scientists say.

People infected with the Alpha variant, which sparked Britain’s devastating second wave in January, are pushing up to 100 times more virus into the air than those who caught the original strain from Wuhan.

That’s according to researchers at the University of Maryland, who say Delta probably transmits even more easily through the air.

Lead author Dr Don Milton said the results indicate that the variants “continue to improve for air travel.”

The study, which was based on monitoring the air that infected volunteers exhale in a machine, also claimed that surgical tissues and masks can halve the amount of virus an infected person exhales.

Experts focused on the Alpha strain – which emerged in Kent last fall and became dominant in the UK in January and the US in March.

This is because it was the predominant strain when they did their research.

Delta, which was first spotted in India last October, quickly overtook Alpha to become the dominant strain in Britain and America in July.

The study, published in the journal Clinical Infectious Diseases, looked at 49 people infected with Alpha and previous strains of the virus – who were asymptomatic or had mild symptoms – between May 2020 and April 2021.

Participants breathed into a machine called Gesundheit-II for 30 minutes without wearing a mask and 30 minutes with a mask.

Volunteers were either asked to repeat the alphabet three times while participating in the study or to sing “happy birthday” three times.

They found that the amount of virus exhaled by people infected with alpha was 43 to 100 times greater than previous strains, depending on the type of particles examined by experts.

But it has already been found that people infected with Alpha have higher viral loads, which means there is more virus in swabs taken from their nose and throat.

When the researchers adjusted to this, they claimed the alpha levels circulating in the air were still 18 times higher than previous versions of Covid.

But when wearing a mask, those infected exhaled 48% less virus, they found.

The finding was true for people wearing surgical or fabric masks.

Researchers have yet to recruit someone who is infected with the Delta strain.

But they claimed their results suggest there will be a “further significant increase in aerosol removal” in people with this strain.

Although airborne transmission of the virus is widely recognized as the primary means by which the virus is spread, studies on how it spreads when it is exhaled and the effect of face masks was previously lacking, the researchers said.

The researchers said their study shows that a “layered approach” that includes improved ventilation, UV air sanitation and well-fitting masks – as well as vaccine deployment – is “essential to protect people in the body. public jobs and interior spaces, ”the researchers said. .

The government announced last month that it installed air purifiers and UV lamps in 30 classrooms as part of a trial to determine whether they have curbed the spread of the virus, with results expected later this year.

Dr Milton said: “Our study provides further evidence of the importance of airborne transmission.

“We know that the Delta variant that is currently circulating is even more contagious than the Alpha variant.

“Our research indicates that the variants keep getting better for air travel, so we need to provide better ventilation and wear well-fitting masks, in addition to vaccination, to help stop the spread of the virus.”

Dr Jennifer German, clinical assistant professor of applied environmental health at the university and co-author of the study, said: “The take-home messages from this article are that the coronavirus can be in your exhaled breath, s’ improves in your exhaled breath, and using a mask reduces the chances that you will breathe it on others.