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.
"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.
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