New lineages of the Omicron COVID variant, like BA.4 and BA.5, are helping spark a wave of reinfections, as people who previously caught COVID-19 contract COVID again.
Now the U.S. Centers for Disease Control and Prevention (CDC) is tracking a new “variant of concern”: BA.4.6. This week, the CDC included the BA.4 spinoff in its weekly tracking of COVID cases, with the agency’s chief data officer tweeting that the new subvariant had actually been “circulating for several weeks” in the U.S. The CDC designates strains as “variants of concern” if they display greater transmissibility, reduced effectiveness of treatment, increased severity, or decreased neutralization by antibodies.