Two coronavirus variants first detected in California are now officially "variants of concern," according to a March 16 update from the CDC.
The variants B.1.427 and B.1.429, both initially identified in California, are classified by the CDC as variants of concern. The three-tier classification system has "variant of high consequence" as the most worrisome group, followed by "variant of concern" and then "variant of interest." No variant is currently considered a variant of high consequence.
Five variants are currently considered variants of concern, including the U.K. variant B.1.1.7, South Africa variant B.1.351 and Japan/Brazil variant P.1.
The California variants are classified as "of concern" because they may be about 20 percent more transmissible, the CDC said, citing early research. It's also unclear if treatments are less effective against the strains.