A subvariant of the highly contagious Omicron coronavirus strain, which some studies indicate could be even more infectious than the original version, has been detected in 57 countries, stated WHO on Tuesday.
In its weekly epidemiological update, the World Health Organization said that Omicron, which accounts for over 93 percent of all coronavirus specimens collected in the past month, has several sub-lineages: BA.1, BA.1.1, BA.2 and BA.3.
The BA.1 and BA.1.1 (the first versions identified) still account for over 96 percent of all the Omicron sequences uploaded to the GISAID (Global Initiative on Sharing Avian Influenza Data) global science initiative, it observed.
But there has been a clear rise in cases involving BA.2, which counts several different mutations from the original — including on the spike protein that dots the virus’s surface and is key to entering human cells.
“BA.2- designated sequences have been submitted to GISAID from 57 countries to date,” WHO said, adding that in some countries, the sub-variant now accounted for over half of all Omicron sequences gathered.
The UN health agency said little was known yet about the differences between the sub-variants, and called for studies into its characteristics, including its transmissibility, how good it is at dodging immune protections and its virulence.
Several recent studies have hinted that BA.2 is more infectious than the original Omicron.
The fast-spreading and heavily mutated Omicron variant has rapidly become the dominant variant worldwide since it was first detected in southern Africa in late November.
Given the nature of the virus, it will continue to circulate and evolve, added the WHO notice, cautioning people on reducing their exposure to the virus and whichever variant is circulating.
