Some people on Oxford Street, some wearing face masks during the third national coronavirus blockade continue on 4 March 2021 in London, United Kingdom.
Mike Kemp | In Pictures | Getty Images
LONDON – The delta sub-variable recently identified in the UK is now twice as prevalent in England as two months ago, a government-backed study found.
Published on Thursday, an update to an ongoing study of Covid-19 in the UK found that the mutation – known as AY.4.2. – accounted for 12% of all new cases of the virus between October 19 and November 5.
The study, which looked at swab samples from 100,000 people in England, was conducted by researchers at Imperial College London and Ipsos MORI, and was commissioned by the UK’s Department of Health and Social Care.
All of the strains identified in the analysis were delta or delta sub-lineages, with AY.4.2. constituting 12% of all positive test samples.
That means the AY.4.2. subvariability has grown by 2.8% every 10 days since late September. It is now Covid’s second most dominant strain, after its predecessor AY.4.
In the week beginning September 27, AY.4.2. accounted for 6% of new Covid cases in the UK, according to the country’s Health Security Agency. By late October, the underlying had accounted for 10% of all new cases.
The subvariate – which is thought to have appeared in the UK over the summer – has two additional mutations affecting its prickly protein, part of the structure of the virus used to infiltrate cells. Questions still hang over exactly how, or if, these mutations will affect how quickly it spreads.
However, scientists have suggested that although AY.4.2. may have a delivery advantage, it is not necessarily a cause for alarm.
AY.4.2 causes milder disease
Thursday’s findings also showed that the AY.4.2. mutation was less likely to cause symptomatic infection than other strains of the virus.
Two-thirds of people with AY.4.2. reported “any symptoms”, compared with more than 75% of those with the UK’s dominant AY.4 strain.
Only a third of those infected with the AY.4.2. a subtype had “classic symptoms of Covid-19” – such as cough or fever – compared with nearly half of the people with AY.4.
The UK registered 38,263 new cases of Covid on Wednesday, and currently has one of the highest infection rates in the world, according to data compiled by Johns Hopkins University.