COVID-19 Variant XE: UK Health Agency On Transmissibility, Infection Rate

Britain's health security agency (UKHSA) has said that it has identified a recombinant lineage of the Omicron strain of coronavirus, which has shown early signs of being even more transmissible than the parent lineage.

The recombinant strain in question has been named as XE. The UKHSA is monitoring three recombinant variants: XD, XE and XF. The XD is the hybrid of BA.1, a sublineage of the Omicron variant and actively found in France, Denmark and Belgium. The XF too is a recombinant version of the Delta and BA.1, but found only in Britain.

The concern is around the XE variant, which the UKHSA says is a recombinant of two sublineages of Omicron - the BA.1 and BA.2. Both the sublineages have led waves of infection in many parts of the world, spreading faster from continent to continent than any known previous strains.

Cases of XE too have been found only in Britain. According to UKHSA, more than 600 people have been found having this recombinant lineage.

What are the concerns around the XE variant?

The UKHSA says that cases of the new sublineage are spreading fast. By March 22, the agency had identified 637 cases that were infected with the XE variant.

After studying the BA.2 samples, the UKHSA arrived at a conclusion that the XE is 9.8 per cent more transmissible. It has, however, clarified that more data is needed before a concrete estimate about its spread can be released.

Talking about the XF variant, the health agency said that only 39 sequences have been identified and only in Britain. All the cases were recorded in January this year and since February 14, no XF-positive sample has been detected.

Previous examples

Recombinant strains have appeared during the continuing spread of the coronavirus infection. Last year, researchers in Japan reported genomic recombination between the Delta and Alpha variants of coronavirus.

In 2020, reports emerged about a recombination of Alpha and B.177 variants in Spain. The scientists are monitoring the mutations and other changes in the virus before determining if currently available vaccines will be effective against them.