#16,889
The Omicron tag-team of BA.4/5 have quickly become the dominant COVID variants across the nation, ending BA.2.12.1's reign after less than 7 weeks on top. While BA.5 has constantly out-performed BA.4, in today's CDC Nowcast, we see BA.4 losing ground for the first time to BA.5.
BA.1.1 - which was dominant in the spring - no longer even registers, while its successor BA.2 is down to 1.4%.
The rapid replacement cycle of Omicron variants has meant that about every 8 to 10 weeks, a new variant soars to dominance, only to be supplanted by the next rising star.
To make matters worse, each new iteration of Omicron has been more transmissible than the last (see Nature: Antibody Evasion by SARS-CoV-2 Omicron Subvariants BA.2.12.1, BA.4, & BA.5).
BA.5 is now nearly 78% of U.S. cases, while BA.4 has fallen to 12.8%. Together they represent a level of dominance we haven't seen since Delta.
Surveillance, testing, and genomic sequencing are limited (and variable) around the country, so Nowcast numbers should be viewed as rough estimates, We may see further revisions to the data in the weeks ahead.
Everything we're seeing suggests that BA.5 (and BA.4) are more likely to evade prior immunity than earlier variants, meaning that even those who have (even recently) recovered from the virus - or have received their booster vaccination - may be at risk of infection.
As a result, hospitalizations have been steadily rising since April (see chart below), albeit nowhere near the peaks we saw last winter.
That said, vaccination (and boosters) - along with prior infection - are still expected to reduce the severity of COVID illness.
Although vaccine manufacturers have recently been tasked with releasing an updated COVID booster with a BA.4/5 Spike Protein component this fall, the big unknown is whether BA.4/5 will even be circulating then - and if not - what will replace it.
Stay tuned.
