Explainer: What is the BA.5 version and why does it seem to be infecting so many people with COVID-19?

People wait to take a coronavirus disease (COVID-19) test at a pop-up testing site in New York City, US, July 11, 2022. Reuters/Brendan McDermid/File photo

LONDON, July 13 (Reuters) – BA.5, part of the Omicron family, is the latest coronavirus variant to cause widespread waves of infection globally.

According to the World Health Organization’s most recent report, it was behind 52% of cases sequenced at the end of June, up from 37% in a week. In the United States, it is estimated to be the cause of about 65% of infections. read more

rising case numbers

BA.5 is not new. First identified in January, it has been tracked by the WHO since April.

It is a sister variant of the Omicron strain that has been in effect worldwide since late 2021, and has caused spikes in case rates – even in countries including South Africa, where it was first detected. That even with less testing. United Kingdom, parts of Europe and Australia.

WHO data shows that worldwide coronavirus cases have been increasing for four consecutive weeks now.

why is it spreading

Like its closely related sibling, BA.4 is particularly good at avoiding the immune defenses afforded by BA.5 vaccination or prior infection.

For this reason, “BA.5 has a development advantage over other subclasses of Omicron that are circulating,” Maria Van Kerkhove, WHO’s technical head on COVID-19, told a news briefing on Tuesday.

For many people, this means they are getting infected again, often even a short time after having COVID-19. Van Kerkhove said the WHO was assessing reports of reinfection.

“We have ample evidence that people infected with Omicron are becoming infected with BA.5. There’s no question about that,” said Gregory Poland, a virologist and vaccine researcher at the Mayo Clinic in Rochester, Minnesota.

If it seems particularly common now, it may simply be because so many people have got an omicron, the researchers suggest.

no more serious

While rising cases have led to more hospitalizations in some countries, deaths have not increased dramatically.

This is in large part because vaccines continue to protect against serious disease and death, if not infection, and manufacturers and regulators are also looking at vaccines that directly target new micron variants.

There’s also no evidence that BA.5 is more dangerous than any other Omicron variant, WHO’s van Kerkhove stressed, although spikes in cases could put health services under pressure and leave more people behind in the long run. You may be at risk of getting COVID.

The WHO and other experts have also said that the ongoing pandemic – prolonged vaccine disparity and the desire in many countries to “move on from Covid-19” – will only lead to more new and unpredictable forms.

Scientists are drawing attention to BA.2.75 already identified in India, which has a large number of mutations and is spreading rapidly.

The WHO said on Tuesday that the pandemic remains a global health emergency, and that countries should consider vaccination as well as public health measures such as masking and social distancing if cases rise. read more

“What people fundamentally don’t understand is that when there is this high level of community transmission, this will change,” Poland said. “Who knows what’s going to happen next. We’re playing with fire.”

Reporting by Jennifer Rigby in London and Julie Steinheusen in Chicago; Editing by Philip Fletcher

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