Nearly 1 in 10 new COVID19 cases in the U.S. are from the BA.2.86 variant, the Centers for Disease Control and Prevention estimated Monday, nearly triple what the agency estimated the highly mutated variant’s prevalence was two weeks ago.
In regions where sufficient specimens have been reported from testing laboratories, the prevalence of the BA.2.86 variant is most pronounced in the Northeast, constituting 13.1% of cases in the New York and New Jersey area. Monday’s data marks the first instance where BA.2.86’s prevalence has reached a level significant enough to be individually identified in the CDC’s estimates. Scientists initially alerted the public to the discovery of this highly mutated strain during the summer.
Previously, BA.2.86 was not distinguished separately in the CDC’s Nowcast updates and was grouped with other BA.2 strains due to its relative rarity. Officials had consistently attributed the majority of new COVID-19 cases to the XBB variant and its closely related descendants, such as the HV.1 and EG.5 variants, which currently dominate nationwide. new COVID19 cases
While the CDC acknowledges substantial margins of error in estimating BA.2.86’s prevalence, ranging from 4.8% to 15.2% of circulating SARS-CoV-2, the latest estimate as of November 25 is 8.8%. This represents a nearly threefold increase from the 3.0% estimated on November 11. The CDC typically releases variant estimates every other Friday, but last week’s release was postponed until after the Thanksgiving holiday weekend.
The agency underscores the caveat that early projections may be less reliable, given their dependence on the examination of growth trends in a smaller number of sequences, especially considering the substantial decrease in laboratory-based testing volume for SARS-CoV-2 over time.