The UK government is keeping a “close watch” on a descendant of the coronavirus Delta variant which is being seen in a growing number of cases.#
Downing Street said it was monitoring the AY4.2 variant but insisted there was no evidence it spreads more easily. While the Delta variant remains the dominant strain in the UK, the latest research shows six per cent of cases that have been genetically sequenced are of a new kind.
the Prime Minister’s official spokesperson said “It’s something we’re keeping a very close eye on. As you would expect we’re monitoring it closely and won’t hesitate to take action if necessary.”
Scientists said AY4.2 carries two characteristic mutations in the spike, Y145H and A222V, both of which have been found in various other coronavirus lineages since the beginning of the pandemic.
However, they have remained at low frequency until now. The first strains carrying both mutations were sequenced in April 2020 and either is found in any variant of concern.
Francois Balloux, professor of computational systems biology at University College London, said: “The A222V was found in the B.1.177 lineage that swept Europe in the summer of 2020. But careful follow-up analyses pointed to the lineage likely having no inherent transmissibility advantage and that its spread was most likely caused by demographic processes. As AY4.2 is still a fairly low frequency, a 10% increase in its transmissibility could have caused only a small number of additional cases. As such it hasn’t been driving the recent increase in case of numbers in the UK. Here we are dealing with a potential small increase in transmissibility that would not have a comparable impact on the pandemic”.
AY4.2 is rare outside the UK and there have been only three cases detected in the US so far.