Omicron sub-variant BA.2 makes up about 55% of Covid variants in US, CDC says

The BA.2 sub-variant of Omicron was estimated to be more than half or 54.9% of the coronavirus variants circulating in the US as of March 26, the US Centers for Disease Control and Prevention (CDC) said on Tuesday.

A resurgence of Covid-19 cases in parts of Asia and Europe has raised concerns that another wave could follow in the US.

Despite the rise of the highly transmissible BA.2 sub-variant, health experts in the US believe that a new wave of infections appears unlikely as overall infections are declining from January’s record highs.

As of March 26, the seven-day moving average of US Covid-19 cases was 27,895, up about 4% from a week earlier.

Last week, top US infectious disease official Dr Anthony Fauci said that although he does not expect a major surge, he would not be surprised to see a rise in cases owing to the increasing dominance of the BA.2 sub-variant.

Most people in the US are now considered to be in low Covid transmission, according to new CDC guidelines introduced last month that emphasised hospital capacity over case counts.

The CDC estimates that BA.2 made up 39%, revised up from 34.9%, of circulating variants in the country for the week ended March 19, 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.