#17,076
BA.5 - the Omicron subvariant which became dominant over the summer - continues to show signs of weakening as a trio of new contenders (
BQ.1, BQ.1.1, and
BF.7) increase their share of cases in this week's
CDC Nowcast report.
While still the predominant strain at 62.2%, it is down from its peak of 86% of cases in late August. BA.4.6 remains in second place at 11.3%, but its share has dropped from its peak 3 weeks ago at 11.9%.
Meanwhile, three subvariants recently added to the Nowcast list are showing the fastest growth, with BQ.1 up over 60% over last week's report, and BQ1.1 up over 25%.
BA.2.75, BA.2.75.2, and BA.4 are little changed from last week, with the caveat being that surveillance, testing, and genomic sequencing are limited (and variable) around the country, so these Nowcast numbers should be viewed as rough estimates. There isn't a lot known about the potential impact of these rising variants (BQ.1 & BQ.1.1), except both are sublineages of the BA.5 variant, with mutations K444T, L452R, N460K, and F486V in the spike protein. BQ.1.1 additionally contains the mutation R346T.
While they both appear to have some enhanced immune escape abilities, the assumption right now is the new bivalent COVID booster should provide some protection against these BA.5 derivatives.
BQ.1 is currently showing the fastest growth, but it may take a few more weeks before the next heir apparent becomes clear.
Given the rapidly expanding field - both here in the U.S. and around the world - the rapid-replacement cycle of COVID variants we've seen for the past year doesn't appear likely to be ending anytime soon.
