- Infections in US have receded sharply since hitting record levels in January.
- Most of the United States is considered to have low transmission.
- CDC estimates BA.2 made up 22.3% of circulating variants for week ending March 12.
The BA.2 sub-variant of Omicron makes up over a third of all coronavirus variants circulating in the United States, according to an estimate from the US Centers for Disease Control and Prevention (CDC) on Tuesday.
COVID-19 infections in the United States have receded sharply since hitting record levels in January, although a coronavirus resurgence in parts of Asia and Europe due to the BA.2 sub-variant has raised some concerns.
As of March 20, the seven-day moving average of US COVID-19 cases was 27,786, down 17.6% from a week earlier.
Most of the United States is considered to have low transmission, under new CDC guidelines introduced last month, which emphasised hospitalization rates and advised most Americans they no longer needed to wear masks.
Other Omicron sub-variants that have been circulating since December —called BA.1.1 and BA.1.1.529 — now make up around 57.3% and 7.9%, respectively, of circulating variants.
The CDC estimates that BA.2 made up 22.3% of circulating variants in the country for the week ending March 12, revised down from 23.1%, according to a CDC model that estimates proportions of circulating variants.
The CDC has in the past revised its estimates as it gets more data.
