Countries in the middle or just past the peak of a surge driven by the BA.5 omicron subvariant, such as the U.S., likely won't experience a subsequent wave from BA.2.75, another omicron relative, some experts predict.
"We're coming to a point where these variants are sort of competing with each other and they're almost equivalent," Dr. Shahid Jameel, a virologist at the University of Oxford in the U.K., told Nature in an Aug. 10 report. "I think people who have had BA.5 will not have breakthrough infections with BA.2.75, and vice versa." Dr. Jameel previously led the SARS-CoV-2 sequencing consortium in India, where BA.2.75 has risen quickly since May. Data suggests about two-thirds of new cases in India are caused by the sublineage, Dr. Shahid told Nature. While BA.2.75 has grown in prevalence there, it has not driven up hospitalization or death rates. In the U.S., BA.2.75 has been detected at very low rates, with some experts contending it is not the next big variant to fret over.
Some researchers suspect a prior wave of cases in India driven by the delta variant helps explain why BA.2.75 is gaining more prevalence there, according to Nature. Delta shares a key mutation with BA.5, also present in India. Thus, delta infections left the population with added protection against BA.5, giving way for BA.2.75 to spread, researchers suspect.
"My guess is that BA.2.75 probably won't prevail that much outside India," particularly in regions that weren't hard hit by delta, Yunlong Richard Cao, an immunologist at Peking University in Beijing who led research on BA.2.75, told the news outlet.
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