Downing Street said it is monitoring the AY4.2 version of the coronavirus, but there is no evidence it spreads more easily
Downing Street said it was monitoring the AY4.2 version, but insisted there was no evidence that it spreads more easily.
While the delta variant remains the dominant strain in the UK, the latest research shows that six per cent of cases that have been genetically sequenced are of a new variant.
“This is something we are keeping a very close eye on,” the prime minister’s official spokesman said.
“As you would expect we are monitoring this closely and will not hesitate to take action if necessary.”
What is AY4.2?
scientists stated that the AY4.2 spike carries two specific mutations in Y145H and A222V, both of which have been found in various other coronavirus lineages since the start of the pandemic.
However, they have remained at a low frequency so far.
The first strains to carry both mutations were sequenced in April 2020 and are found in either strain of concern.
François Balloux, Professor of Computational Systems Biology at University College London, said: “A222V was found in B1.177 lineage that had drifted Europe in the summer of 2020.
“But careful follow-up analyzes pointed to ancestry with no inherent communicability advantage and that its spread is likely due to demographic processes.”
They noted that neither mutation was a clear candidate for increased transmissibility, but the mutation can have different, sometimes unexpected, effects in different strains.
“As AY4.2 is still at a fairly low frequency, a 10% increase in its transmission efficiency could only lead to a few additional cases,” explained the professor.
“As such it is not driving the recent increase in the number of cases in the UK.”
He said that AY4.2 could not be compared to the emergence of alpha and delta, which were at least 50 percent more transmissible than any other strain at the time.
“Here we are dealing with a potentially small increase in transmittance that will not have a comparable impact on the pandemic,” he said.
AY4.2 is rare outside the UK and only three cases have been detected in the US so far.
In Denmark, it reached a 2% frequency, but has since gone down.
Work is underway to test whether it can be less well recognized by antibodies.