#16,740
According to this week's Nowcast from the CDC, the percentage of BA.2.12.1 cases continues to rise - but not quite as fast as earlier reports suggested - reaching an estimated 42 % of U.S. cases last week; up from a (revised) 33% 7 days ago.The percentage of B.1.1.529 and BA.1.1 - both of which have been dominant strains in 2022 - has dropped to less than 1%, and BA.2 - the current leader - continues to give ground to BA.2.12.1.
Although it has taken a bit longer than many expected, within the next week or two BA.2.12.1 will likely become the dominant strain here in the United States. We don't have any evidence that BA.2.12 produces any greater severity of illness than BA.2, but we are seeing rising infections in some parts of the nation.
Given the limits of surveillance, testing, and genomic sequencing around the country, all of these numbers should be viewed as rough estimates, and we may see further revisions to the data in the weeks ahead.
The big unknown is what comes next.
Since the emergence of Omicron (B1.1.529) last November, we've seen newer, more transmissible variants (BA1, BA1.1, BA.2, etc.) emerge and rise to dominance every 6 to 8 weeks. Many are looking at BA.4 and BA.5 - currently circulating in South Africa and recently detected in the UK - as the next likely heir apparents.
As long as this rapid replacement cycle continues, reports of the pandemic's imminent demise are likely premature.
