As BA.2 subvariant of Omicron rises, lab studies point to signs of severity

 

 The BA.2 virus -- a subvariant of the Omicron coronavirus variant -- isn't just spreading faster than its distant cousin, it may also cause more severe disease and appears capable of thwarting some of the key weapons we have against Covid-19, new research suggests.
New lab experiments from Japan show that BA.2 may have features that make it as capable of causing serious illness as older variants of Covid-19, including Delta.
And like Omicron, it appears to largely escape the immunity created by vaccines. A booster shot restores protection, making illness after infection about 74% less likely.
BA.2 is also resistant to some treatments, including sotrovimab, the monoclonal antibody that's currently being used against Omicron.The findings were posted Wednesday as a preprint study on the bioRxiv server, before peer review. Normally, before a study is published in medical journal, it is scrutinized by independent experts. Preprints allow research to be shared more quickly, but they are posted before that additional layer of review.
"It might be, from a human's perspective, a worse virus than BA.1 and might be able to transmit better and cause worse disease," says Dr. Daniel Rhoads, section head of microbiology at the Cleveland Clinic in Ohio. Rhoads reviewed the study but was not involved in the research.
BA.2 is highly mutated compared with the original Covid-causing virus that emerged in Wuhan, China. It also has dozens of gene changes that are different from the original Omicron strain, making it as distinct from the most recent pandemic virus as the Alpha, Beta, Gamma and Delta variants were from each other.
Kei Sato, a researcher at the University of Tokyo who conducted the study, argues that these findings prove that BA.2 should not be considered a type of Omicron and that it needs to be more closely monitored. "As you may know, BA.2 is called 'stealth Omicron,' " Sato told CNN. That's because it doesn't show up on PCR tests as an S-gene target failure, the way Omicron does. Labs therefore have to take an extra step and sequence the virus to find this variant.
"Establishing a method to detect BA.2 specifically would be the first thing" many countries need to do, he says.
"It looks like we might be looking at a new Greek letter here," agreed Deborah Fuller, a virologist at the University of Washington School of Medicine, who reviewed the study but was not part of the research.