Health chiefs claim that Covid vaccines seem to work as well against the more transmissible Delta variant offshoots as they do against its ancestor.
The UK Health Security Agency, which replaced the defunct Public Health England (PHE), found that jabs were around 81% effective in stopping people infected by AY.4.2 from getting symptomatic.
Two doses of the original strain are believed to prevent around 83% of people from getting sick with it.
UKHSA claimed that the results do not indicate a significant drop in vaccine effectiveness for the AY.4.2 vaccine compared with Delta, and admitted that there may have been a slight dip.
It was found that the strain has increased in frequency to 23,830 UK cases as of Monday, the most recent date data is available. However, the true number could be 10 times greater because only a handful of infections are being sequenced in Britain.
The variant has now been found in all but a dozen corners of England and makes up one in ten new cases — doubling in the space of a month.
Although data shows it is still outcompeting its ancestral strain, scientists are now questioning whether the subtype is actually more transmissible than Delta. Experts initially believed the strain to be 10 to 15% more infectious.
Figures show that while the number of cases of the mutant strain is increasing, its curve flattens. It is growing slower that its predecessor, which was sequenced at the same time, at this point.
Early tests today have shown that Covid vaccines are just as effective against the more transmissible Delta offshoot. Graph shows: The cumulative numbers of cases for each Covid variant, including Delta (lilac), and AY.4.2(red) since the fifth case was reported. The curve of the mutant strain is flattening, even though its cases are increasing. It is growing slower than its predecessor at this point in the sequence.
As of October 25, the variant was most prevalent among people aged 10 to 19, with 5,473 people having been infected. They were followed closely by 40-to-49-year-olds (2.433), 30-to 39-years old (2.015), and 20 to 29-years-olds (1.900).
Regionally, the South West had the highest number of AY.4.2 cases in the week ending October 18 — reflecting overall infection numbers — with 426 sequenced during the week
The above chart showed AY.4.2 accounted for a slightly higher proportion of cases in the latest week — one in ten — compared to two weeks ago — one in 13. Scientists believe the slow rise is still compatible with a 10% transmission advantage over Delta.
The map above shows the 12 areas where AY.4.2 was not found in (white) during the two weeks leading up to October 16, when the latest information became available. It has spread to almost all areas of England
The new Covid variant AY.4.2 was found in 42 countries but is most prevalent in the UK. This graph shows how AY.4.2 cases are compared to total Covid cases in each country. Since July’s identification of the variant, the UK has led case growth. However, in recent weeks Poland has eclipsed it and there are signs that Germany is also catching up.
The UKHSA indicated that there was little to worry about the variant’s ability to evade vaccines better than Delta.
According to the agency, there was no evidence that AY4.2 had any significant differences in symptoms or asymptomatic levels from non-AY4.2 Delta patients.
It discovered that all vaccines against the variant were equally effective.
It comes after WHO this week admitted that it had no records of the variant.
Experts raised questions this week about whether the new strain was actually more transmissible than what was previously suggested by the data.
Researchers at Northumbria University who are involved in variant surveillance claim that it is still ‘unclear” if AY.4.2 can be transmitted more easily because of the lack of information about its mutations.
They suggested the ‘founder Effect’ as an alternative explanation. This is when a strain spreads quickly if it is the only one among a particular group of cases, such as a school.
Professor Francois Balloux at University College London, a geneticist, and Covid commentator, raised concerns about the variant last Wednesday. He said that the slower rise was’still compatible with’ a 10% transmission advantage.
Professor Jeffrey Barrett, head, Covid surveillance at Sanger Institute, stated that the data showed ‘consistently with a small but real growth advantage vs. other Delta’.
According to UK-based tracking, this sub-variant was first identified in the UK on June 26.
Scientists believe that AY.4.2 developed in the UK due to its higher number of cases than other nations.
However, it is possible for the variant to have been imported from abroad and spread in the country due to worse variant surveillance than the UK.
It contains two key mutations: A222V, and Y145H. These both slightly alter the form of spike protein, which the virus uses in order to invade cells.
Scientists claim that A222V was first seen on a variant (B.1.177), which was first discovered in Spain, before spreading to other countries.
However, studies show that the strain was not more transmissible and was spread only by holidaymakers returning to their homelands.
More concern is expressed about the mutation Y145H. This slightly alters the site to which antibodies bind, making it more difficult for them to stop infection from happening.
Scientists believe this mutation is due to mutations in Delta and could make the subtype more resistant than its parent to vaccines.
AY.4.2 has been reported in more than 40 countries so far, but the UK is currently the only country experiencing a sustained outbreak.
It was around one in 50 Covid cases for Denmark in September. But it has now fallen to less than one in 100. Experts in the nation say they are not concerned by AY.4.2.
Officials from the UK declared it a ‘variant under examination’ last week. This is for variants that are spreading in the UK and may be more transmissible, or better able evade vaccines than others mutant strains. However, it is still below the ‘variant under investigation’ category which includes Alpha and Delta.