The has rapidly spread to become the dominant COVID-19 mutation in the U.S., now accounting for 40.5 percent of all cases.
The XBB.1.5 omicron subvariant as of this week has pushed out the BQ.1 and the BQ.1.1 subvariants from their previous positions as the most detected coronavirus mutations, according to surveillance conducted by the Centers for Disease Control and Prevention (CDC).
The XBB subvariant, from which XBB.1.5 descends, is a recombinant of two subvariants that descended from the BA.2 omicron subvariant. That means it carries genetic data from two versions of the coronavirus that originated from the BA.2 subvariant.
Regionally, XBB.1.5 now accounts for the majority of COVID-19 cases in the northeast, identified as causing 75 percent of cases in New England and in the New York tri-state area.