New Omicron strains capable of evading immune protections and causing breakthrough infections now account for more than 21% of total COVID cases in the U.S., according to updated CDC figures.
Why it matters: The virus continues to evolve, with the BA.4 and BA.5 lineages accounting for a bigger proportion of the approximately 105,000 new daily cases.
- The BA.2 and BA.2.12.1 lines that dominated the disease map this spring now account for about 78% of cases.
- The new lineages aren't associated with more severe disease.
- But they're thought to be able to evade antibodies from earlier Omicron infections.
Go deeper: Overall cases are still declining in the Northeast but increased elsewhere in the past week. The regional mix is now 30% from the South, 29% West, 22% Northeast and 20% Midwest, per Evercore ISI.
- The updated figures are almost certainly an undercount, because many at-home test results go unreported.
Looking ahead: The changes in the variant mix will provide more fodder for FDA outside advisers, who'll meet later this month to evaluate how COVID vaccines are updated and possibly selected this fall.
