Scientists are anxiously tracking a descendant of the Delta coronavirus, which is responsible for a growing proportion of Covid-19 cases in the UK, and could be more infectious than the original Delta variant, they say.
This AY.4.2 subvariant has only recently been recognised by virologists who follow the genetic evolution of Delta but it already accounts for almost 10 per cent of UK cases. Its prevalence is increasing rapidly, though not as fast as the original Delta variant when it reached Britain from India early this year.
Two experts — Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute in Cambridge, and Francois Balloux, director of the University College London Genetics Institute — said AY.4.2 seemed to be 10 to 15 per cent more transmissible than the original Delta variant, which has come to dominate Covid cases around the world.