2 new studies suggest BA.2.86 less immune-evasive than feared
IANS Sep 09, 2023
Amid fresh concerns about COVID-19 due to the new highly mutant Omicron subvariant BA.2.86, two new studies from the US have confirmed that it is less contagious as well as immune evasive.
This comes after two studies last week from China’s Peking University and Karolinska Institutet in Sweden showed that the variant is less transmissible than XBB and EG variants.
The new study, led by researchers from Beth Israel Deaconess Medical Center in the US, reported on X, that their first data from their antibody neutralisation experiments suggest responses to BA.2.86 were lower than to BA.2.
However, they were comparable to or higher than the current circulating variants. Neutralising antibodies to all variants, including BA.2.86, increased following XBB infection.
The experiments were done on samples from 66 people, including 44 who had received the bivalent (two-strain) mRNA COVID booster, said Ninaad Lasrado, one of the researchers at the Barouch Lab at the Centre, on X.
He added that the findings fuel hopes that the new XBB.1.5 vaccines have the potential to induce cross-reactive neutralising antibodies against other recombinants and against BA.2.86.
According to Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at the Center, their results align with earlier experiments by labs in China and Sweden.
Taken together, the data suggests that BA.2.86 will not be as troublesome as experts had feared. In short, this one seems to be a "scariest", he was quoted as saying to CNN.
But another variant, FL.1.5.1, which is causing an estimated 15 per cent of new COVID-19 infections in the US, maybe a different story.
This fast-growing descendant of the XBB recombinant variant has a constellation of mutations that have raised the eyebrows of variant trackers.
In lab testing, it was the most immune-evasive. "If there wasn’t so much hype about BA.2.86, that would actually be the focus of the paper," Barouch said.
In the second study, researchers at Columbia University used blood plasma from 61 adults: 17 who had gotten three monovalent vaccine doses and two bivalent vaccines, 25 who had recovered from a BA.2 breakthrough infection and 19 who had recovered from an XBB breakthrough infection. The results were substantially similar to the study at Barouch lab, the report said.
Across the range of immune profiles, antibodies in the blood were able to recognise BA.2.86 just as capable as they were other circulating variants. People with the highest degree of immunity against BA.2.86 were those who recovered from recent XBB infections.
That was a surprise because of how many mutations BA.2.86 has. Scientists had predicted that based on what was known about those specific mutations, it might be highly immune-evasive, the report said.
"The news is better than I was expecting and makes me more encouraged that the new upcoming vaccine will have a real benefit against the current dominant variant (EG.5) as well as BA.2.86," Dr Ashish Jha, former White House COVID-19 response coordinator, in a post on X.
BA.2.86, which descended from an Omicron variant, has so far been linked with 29 cases of COVID across four continents. The variant has been detected from both human and wastewater specimens. So far, it has not been found to cause more severe illness.
But the limited number of cases means it’s too soon to know whether it causes more severe COVID-19 or is more transmissible than other variants.
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