The UK Health Security Agency has designated the Omicron variant sub-lineage known as BA.2 as a VUI, or Variant under Investigation*.
Just 53 sequences had been identified in the UK by 10 January, according to the UKHSA, but the variant is already at ~50% of cases in Denmark and has grown rapidly in January.
BA.2 is still at fairly low levels in the UK at present:
Although confirmed BA.2 numbers in the UK are currently very small, with just 72 cases identified by genome sequencing up to the 8th January 2022, that figure is a tenfold increase from the previous week when it was just 7 cases.
The latest estimate for BA.2, again up to 8th January 2022, is 1641.
In Denmark, BA.2 represents about 50% of new cases recently:
Infections are still increasing dramatically in Denmark, although Omicron waves are levelling off in many other countries.
Denmark have said that BA.2 in not causing an increase in hospitalizations, but Danish hospitalization numbers have been increasing recently:
UPDATE 1 – 21st January 2022: “The UKHSA announced that they had classed BA.2 as being a variant under investigation in a tweet, but this was later hastily deleted.” (Daily Mail)