Omicron and its descendent lineages are still the dominant COVID 19 variant globally but have declined in relative prevalence, according to the World Health Organization.
Globally, the WHO counted nearly 10.5 million new cases in the 28 days through Feb. 5, down 89% from the previous 28-day period. The agency changed its reporting schedule last week to every 28 days from weekly in order to help smooth out fluctuations and delays in reporting numbers.
In the week through Jan. 22, they accounted for 53.9% of prevalence among sequences submitted to a central database, down from 74.2% in the week through Dec. 25, the agency said in its weekly epidemiological update.
Pooled recombinant variant sequences rose to 24.6% from 8.8%, mostly due to XBB.1.5, which is dominant in the U.S. where most sequences were reported.
The WHO is currently tracking four omicron descendent lineages closely, namely BF.7; BQ.1 and its lineages; BA.2.75 and its lineages; and XBB and its lineages.
“These variants are included on the basis of signals of transmission advantage relative to other circulating variants and additional amino acid changes that are known or suspected to confer fitness advantage,” said the update.