- BBC News World
UK health authorities are closely monitoring a new mutation in the delta variant of the coronavirus that is causing an increase in covid cases.
Delta is the dominant variant in this country, but the latest official data suggests that 6% of covid cases that have been genetically sequenced are of a new type, the so-called AY.4.2 or delta plus.
The delta plus variant, which was first confirmed in the United Kingdom in July 2021, has already been identified in at least 44 countries, according to data from the outbreak.info portal, which collects global covid data.
And, according to experts, it contains mutations that could give the virus survival advantages.
Analysis is currently being carried out to understand what degree of threat it may pose.
But it is believed to be unlikely to cause an accelerated rebound or escape the protection of current vaccines.
The categories assigned to the variants and their level of risk are not yet considered a variant of concern or a variant under investigation.
What is AY.4.2?
There are thousands of different types or variants of covid circulating around the world.
Viruses mutate all the time, so it’s not surprising that new versions emerge.
The original delta variant was classified as a worrying variant in the UK in May 2021 after it overtook the alpha variant and became the dominant type of covid in circulation.
But in July 2021, experts identified AY.4.2.
Since then, the cases of this descendant -or sublineage- of the delta variant he hasn slowly increasing.
Delta plus includes some new mutations that affect the spike protein, which the virus uses to penetrate our cells.
So far, there is no indication that it is significantly more transmissible as a result of these changes, but it is something that experts are studying.
Since the beginning of the pandemic, delta plus mutations – Y145H and A222V – have been found in several other coronavirus lineages.
Michelle Roberts analysis,
BBC Health Editor
Scientists are constantly looking for the new genetic changes that the coronavirus is undergoing.
Some emerging variants are worrisome, but many are inconsequential.
The hard job is spotting, tracking, and managing the ones that might be important.
The UK is a pioneer in carrying out these vital laboratory tests, having carried out more than a million tests so far.
The first step is to choose the new mutations that deserve surveillance, such as this new AY.4.2 sublineage.
Then, if there is a strong indication that genetic changes could make the virus more contagious, it is classified as a variant under investigation and further testing is done.
If it becomes clearer that the mutation could be more transmissible and could escape the immunity built up by past infections or vaccines, or that it could cause more serious disease, it is placed in the category of variant of concern. The delta is currently in this category.
So far experts do not believe that AY.4.2 is likely to become established, so it could eventually die out and disappear from the watch list.
Professor Francois Balloux, Director of the Institute of Genetics at University College London, points out that “it is potentially a slightly more infectious strain. “
“It doesn’t compare at all to what we saw with alpha and delta, which were 50-60% more transmissible. So here we are talking about something quite subtle and currently under investigation.”
“It is likely to be up to 10% more transmissible.”
“It is good that we are aware. It is excellent that we have the facilities and infrastructure to see anything that may be a little suspicious.”
“At this stage, I would say that we wait and observe, that there is no panic. It may be a little more transmittable, but it is not something absolutely disastrous as we saw previously,” says the expert.
The British government says that the new variant “is being watched very closely” and that “action will be taken if necessary”.
But the experts do not believe that this sublineage is responsible for the drastic increase recent UK covid infection cases.
“As AY.4.2 is still at a fairly low frequency, a 10% increase in its transmissibility could have caused only a small number of additional cases,” explains Professor Balloux.
“As such, it has not fueled the recent increase in the number of cases in the UK,” he adds.
The UK is already offering booster doses of the vaccine to people most at risk before winter to ensure they have maximum protection against the coronavirus.
There is no suggestion that a new vaccine update is needed to protect against any of the currently circulating variants of the pandemic virus.
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