An offshoot of the delta coronavirus variant, which is slowly spreading across the UK, is expected to dominate within a few months, experts believe.
The sub-variant known as AY.4.2 is considered to be at least 10 cents more transferable than its predecessor, although it is currently being analyzed what is responsible for its increased infectivity.
The UK Health and Safety Authority (UKHSA) has stated that early testing does not indicate that AY.4.2, which has been labeled as an “Investigative Variant”, has acquired the ability to evade immunity generated by infection or injection.
The new mutations in the sub-variant are also not linked to any significant improvement in the virus’ ability to bind and enter human cells, experts said.
Nonetheless, AY.4.2 accounts for a growing proportion of cases every week. Between October 18 and October 24, they accounted for 11.3 percent of all sequenced infections in the UK. Two weeks earlier, this value was 8.5 percent.
Dr. Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute, said each week of additional data “increases confidence that AY.4.2 has an inherent growth advantage” over the original Delta variant that took off in the UK.
Given its current trajectory, AY.4.2 will eventually supplant its Delta predecessor and potentially become dominant in January, said Dr. Barrett. “I think it will happen,” he added. Separate analysis has suggested that the sub-variant could catch on in the UK as early as December.
Ravi Gupta, a professor of clinical microbiology at Cambridge University, said these estimates depend on the methodology used for modeling, adding that he was not convinced that AY.4.2 will dominate the winter months.
Fears have been expressed about the emergence of AY.4.2 and its possible impact on the direction of the UK epidemic. Dr. Barrett suggested, however, that the line would likely not prove disastrous for Britain.
“All other things being equal, it will add a modest amount to cases and hospital admissions, but it’s a much smaller relative change than Delta compared to Alpha, so things won’t change that fundamentally,” he said.
Emma Thomson, professor of infectious diseases at the University of Glasgow’s Center for Virus Research, said it is still unclear why AY.4.2 is increasing.
“It doesn’t have any classic mutations that would lead us to believe that it is more transmissible or that it might evade immunity, although we are currently investigating this because of the increasing numbers,” she said.
“We were surprised beforehand, and until the experiments are finished, I wouldn’t be one hundred percent sure that this variant doesn’t have a small advantage.”
AY.4.2 is the second notable variant of Covid to appear in the UK, after Alpha that entered the population last Christmas.
Scientists have said that the current high rate of infection across the UK makes it “inevitable” that other variants will emerge in the future.
“AY.4.2 is not the underlying problem,” said Professor Sam Wilson, virologist at the University of Glasgow’s Center for Virus Research. “The problem is that a relatively uncontrolled spread of the virus increases the likelihood that more problematic variants will arise.”
Prof. Gupta said, “Again, the focus is on our lack of intervention. Variants with high transferability will inevitably be added. “
The emergence of a seemingly more easily transmissible variant of Covid has also raised concerns that the virus is still evolving to better adapt to the human population and has not yet peaked.
“It’s a bit frustrating because I think I’m not the only one who was hoping we saw essentially the most transmissible variant with Delta,” said Professor Francois Balloux, director of the Genetics Institute at University College London . “I think it will be a bit of a setback, but not so much.
“I’m less worried about the variant itself, but let’s say I’m a little worried that we have actually not yet achieved maximum transferability.”
Dr. Barrett said there was no indication of “how far it goes”. [the virus] has to go, only that it has not yet reached its optimum ”.