Washington: New Omicron subvariants have led to increasing Covid-19 cases in the US, with BQ.1 and BQ.1.1 accounting for over 35 per cent of the new infections this week, according to the Centers for Disease Control and Prevention (CDC).
BQ.1.1 made up 18.8 per cent of circulating variants, and BQ.1 was estimated to make up 16.5 per cent of circulating cases in the week ending November 5, Xinhua news agency reported citing the CDC data.
The two variants accounted for about one quarter of new Covid-19 infections nationwide in the week ending October 29, CDC data showed.
The two new variants have been growing especially fast since October.
At the beginning of October, each one accounted for about 1 per cent of new infections in the US, but they have been roughly doubling in prevalence each week.
The predominant Omicron lineage in the Us remains BA.5, which accounted for 39.2 per cent of new infections in the latest week, CDC data showed.
SARS-CoV-2, the virus that causes Covid-19, is constantly changing and accumulating mutations in its genetic code over time, says the CDC.
New variants are expected to continue to emerge, it added.
As of Wednesday morning, the overall Covid caseload and death toll in the US stood at 99,697,922 and 1,098,524, respectively.