New Delta subvariant that’s ‘spiking in UK’ could be up to 15% more infectious – as cases hit three-month high
A NEW subvariant of the Delta strain is on the rise in the UK - that could be up to 15 per cent more infectious.
It comes as the UK saw the highest number of new daily cases in three months yesterday - with 49,156 infections recorded.
The spike in cases of AY.4.2 has been picked up in Britain, with a slice of the country's growing infections due to the subvariant.
The former US Commissioner of Food and Drugs Scott Gottlieb called for an urgent investigation into the rise.
He called it "Delta plus", which was a name given to an earlier separate strain, but tweeted: "UK reported its biggest one-day Covid case increase in three months just as the new delta variant AY.4 with the S:Y145H mutation in the spike reaches 8% of UK sequenced cases.
"We need urgent research to figure out if this delta plus is more transmissible, has partial immune evasion?"
Experts have said "wait and see" and "don't panic", but as the booster jab rollout stutters, there are fears of a quicker spread as we come into winter.
Professor Francois Balloux, director of the University College London Genetics Institute, said: "It is potentially, marginally more infectious strain, now it's nothing compared to say what we saw with Alpha.
"We are talking about something quite subtle here and currently under investigation."
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He said it can't be pinned on the rise in cases at the moment, but he also warned it could be the most infectious strain since the pandemic started if it does take off.
He told Radio 4: "In the UK it's still going up, about 7/8 per cent, it's slowly rising. In the UK it's doing reasonably well.
"I think it's always excellent to be able to prepare for what's coming but I'd really like to stress it's not the same kind of scenario that we saw first with Alpha and then Delta.
"It is likely to be up to ten per cent more transmissible. It might be subtly more transmissible but it's not something absolutely disastrous that we saw previously.
"The tests in the lab are still underway - from a purely bioformative point of view it's not obvious how it could achieve that [escape vaccines], so I don't expect it to be able to escape vaccines more.
"It's so transmissible it can often break through, not because our immune system doesn't recognise it but just because it's so infected."
Almost half of new Covid cases in England are now among the under-20s, figures show.
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It is possible that it has taken off so quickly in the UK due to the limited social distancing guidelines in place now, and many people back in the office and fully socialising again.
Downing Street has said it is keeping a close eye on the AY4.2 coronavirus variant but insisted there is no evidence it spreads more easily.
The Prime Minister's official spokesman said: "It's something we're keeping a very close eye on.
"There's no evidence to suggest that this variant... the AY4.2 one... is more easily spread. There's no evidence for that but as you would expect we're monitoring it closely and won't hesitate to take action if necessary."
Last winter the country was forced back into lockdowns after the Alpha variant began to rip through Britain.
It comes as thousands of people must retake their coronavirus tests because a dodgy lab exposed by The Sun was giving false negative results.
At least 43,000 people given the all-clear in September and October might have had Covid.
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Work has been halted at the Immensa Health Clinic in Wolverhampton over the surge in negative PCR tests following positive lateral flow results.
Most are in the West Country. The lab got a £119million taxpayer-funded contract last year months after launching.
All you need to know about the subvariant:
What mutations does AY.4.2 carry?
Professor Francois Balloux: “A new SARS-CoV-2 lineage has gone up in frequency in the UK. It has been defined as AY.4.2. It is a descendant of the Delta (B.1.167.2) variant. It carries two characteristic mutations in the spike, Y145H and A222V.”
What other variants are they present in?
“Most SARS-CoV-2 mutations have independently emerged many times in unrelated strains. Both the spike Y145H and A222V mutations have been found in various other SARS-CoV-2 lineages since the beginning of the pandemic, but have remained at low frequency until now. The first strains carrying both mutations were sequenced in April 2020. Neither are found in any Variant of Concern.
“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.”
What do we know about their effect on transmissibility/severity?
“Neither mutation is a priori an obvious candidate for increased viral transmissibility, but we have learnt that mutations can have different, sometimes unexpected, effects in different strains.”
How is it being investigated?
“The AY.4.2 is being closely monitored in the UK and elsewhere. It remains rare outside the UK. There have been only three cases detected in the US so far. In Denmark, the other country that besides the UK has excellent genomic surveillance in place, it reached a 2% frequency but has gone down since. In addition, functional work is underway to test whether it may be less well recognised by antibodies.”
Could it explain the recent rise in UK cases?
“As AY.4.2 is still at fairly low frequency, a 10% increase its transmissibility could have caused only a small number of additional cases. As such it hasn’t been driving the recent increase in case numbers in the UK.”
- Should we be concerned?
“The emergence of yet another more transmissible strain would be suboptimal. Though, this is not a situation comparable to the emergence of Alpha and Delta that were far more transmissible (50% or more) than any strain in circulation at the time. Here we are dealing with a potential small increase in transmissibility that would not have a comparable impact on the pandemic.”
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