A branch of the Delta coronavirus virus that appears to be more transmissible than its predecessor has begun to spread across England, scientists have said.
Little is known about the AY.4.2 sub-version, but recently published data suggests it was responsible for six percent of new infections in the week starting September 27. A UK Health Protection Agency briefing said AY.4.2 is “expanding” and “on an increasing trajectory”.
Experts have estimated that it may be 10 to 15 percent more transmissible. Compared to the original Delta version, which has come to dominate around the world.
Dr Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute, said it would be “annoying but not devastating” for the UK in the coming months.
However, he wrote on Twitter, “Perhaps more worryingly, it suggests that the virus still has evolutionary routes to high transmittance, and there are millions of delta cases worldwide without any sequencing coverage.”
Professor Francois Balloux, Director of the Genetics Institute at University College London, said the recent spike in UK cases cannot be attributed to AY.4.2 alone.
“As AY.4.2 is still at a fairly low frequency, a 10 percent increase” [in] Its transmissibility can only lead to a few additional cases,” he said. “As such it is not driving the recent increase in the number of cases in the UK.”
The sub-variant carries two mutations in its spike protein, termed Y145H and A222V, that have emerged independently in other forms, suggesting that they may prove highly problematic.
“Neither mutation is a priori a clear candidate for increased viral transmissibility, but we have learned that mutations can have different, sometimes unexpected, effects in different strains,” Professor Balloux said.
Ravi Gupta, Professor of Clinical Microbiology at the University of Cambridge Guardian that mutations similar to Y145H were observed in other variants that had minor effects on antibody response.
For now, AY.4.2 is rare outside the UK. Three cases of the sub-version have been detected in the US so far, while Denmark – renowned for its genomic surveillance – has also picked up a small number of AY.4.2 infections, Professor Balloux said.
He described the emergence of the sub-version as “sub-optimal”, adding that “it is not a condition comparable to the emergence of alpha and delta that are far more permeable (50 percent) than any strain in circulation. or more). Time.”
Prof Balloux said: “Here we are dealing with a potentially small increase in transmissibility that will not have a comparable impact on the pandemic.”
Dr Barrett said it may only be a “temporary” one that AY.4.2 has managed to establish itself in the UK, but not elsewhere, adding that it “really needs to be established somewhere” to avoid burnout. ” would be required.
“That is, landing 20 Delta transitions with only Alpha almost guarantees it will lead to a complete replacement, whereas 20 AY.4.2 landings may well fizzle out in the current Delta pandemic,” he said.
Credit: www.independent.co.uk /