Omicron BA.2 makes up over 35% of total Covid-19 variants circulating in US
PremiumOther Omicron sub-variants that have been circulating since December—called BA.1.1 and BA.1.1.529—now makeup around 57.3% and 7.9%, respectively, in US
The Omicron BA.2 sub-strain is contributing to over a third of all variants circulating in the United States, said the Centers for Disease Control and Prevention (CDC) on Tuesday.
Other Omicron sub-variants that have been circulating since December—called BA.1.1 and BA.1.1.529—now makeup around 57.3% and 7.9%, respectively, of circulating variants.
Covid-19 infections in the US have receded sharply since hitting record levels in January. As of 20 March, the seven-day moving average of the infections was 27,786, down 17.6% from a week earlier.
The CDC estimates that BA.2 made up 22.3% of circulating variants in the country for the week ending 12 March, revised down from 23.1%, according to a CDC model that estimates proportions of circulating variants.
Most of the US is considered to have low transmission, under new CDC guidelines introduced last month, which emphasized hospitalization rates and advised most Americans they no longer needed to wear masks.
However, a coronavirus resurgence in parts of Asia and Europe due to the BA.2 sub-variant has raised some concerns.
Upticks are visible again in France, Italy and the UK. Infection rates in both Austria and Germany eclipse previous waves of the virus (based on cases per million). China is grappling with new highs in terms of case counts.
Experts have said that the new wave is mostly being driven by countries removing pandemic restrictions right around when the more transmissible Omicron BA.2 subvariant began to spread.
In the UK, the end of mask mandates on public transport and required self-isolation if infected has led many people to drop their cautionary behavior and allowed BA.2 infections to gather pace.
Data from Denmark and Sweden, the two countries where BA.2 got an early foothold, suggest that waning immunity isn’t so much driving the rise in infections as BA.2’s superior ability to infect people.
The picture in the US is less clear. In the past two Covid waves, the trajectory of US infections lagged Europe by a few weeks, so the same thing may happen this time too.
One factor in the US's favor is that the BA.1 omicron wave probably infected a larger proportion of the US population than in most European countries, so the immunity from that could limit the duration of the BA.2 wave as well as its severity.
With inputs from agencies.
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