COVID-19: Enhanced contact tracing and testing for 'Delta plus' variant after 41 cases identified in UK

Measures including enhanced contact tracing and testing have been put in place after the UK identified dozens of cases of the "Delta plus" variant.

Speaking this afternoon, the prime minister's spokesman said the government and Public Health England had put the precautions in place where the new coronavirus variant had been identified.

He added that 41 cases had been found in the UK, and "enhanced contact tracing, testing, and isolation" were among the steps taken.

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Cases of the variant have been identified in the East Midlands, London, the North West, South East, South West and West Midlands as of 14 June.

It was first sequenced in the UK on 26 April, and the initial five people to be identified with it had been in contact with individuals who travelled through or from Nepal and Turkey.

These cases were all in the West Midlands.

The Delta plus variant is similar to the original Delta strain, with an additional mutation called K417N.

Officials in India have said the strain appears to be more transmissible than the base Delta - or B.1.617.2 - variant.

The country has labelled the strain a "variant of concern", after 16 cases were found in the state of Maharashtra.

However, Francois Balloux, professor of Computational Systems Biology and the director of the University College London Genetics Institute, says there is less to be concerned about.

Professor Balloux said: "Cases of the Delta plus variant in the UK remain at a very low level. The first case was observed on 28 April 2021. The lineage has remained at very low frequency since with no sign of expansion."

The scientist added that the low number of cases of this variant wherever it has appeared "strongly suggest it is not more transmissible than its Delta progenitor".

Public Health England's latest report on variants - published on Friday but only recently coming to attention - confirms 41 of the 75,953 Delta variant cases sequenced in the UK had the K417N mutation.

As well as India, the PHE document stated that cases of the strain had also been identified in other countries, with one in Canada, 15 in Japan, three in Nepal, nine in Poland, 22 in Portugal , one in Russia, 18 in Switzerland, one in Turkey and 83 in the US.

Professor Balloux says this kind of mutation has arisen a number of times across the pandemic - including in the Beta variant first identified in South Africa.

He added: "The [K417N] mutation may contribute to immune escape, though its impact on transmissibility is not clear-cut.

"None of the lineages carrying it (with the exception of Beta) have been particularly successful so far."

Experts have repeatedly said that the coronavirus will mutate constantly over time, with some variants posing a risk, as they could escape the immune system.

PHE has said two doses of both the Oxford-AstraZeneca and Pfizer-BioNTech vaccines are effective against the Delta variant - but more data would be needed on a further mutation.

Speaking at a Downing Street press conference on Wednesday, PHE head of immunisation Dr Mary Ramsay said she was "not convinced" that the Delta variant had symptoms different to other COVID strains.

Pressed on people reporting sneezing as a symptom of the new variant, she replied: "I've seen the data that you talk about that there might be a slightly different symptom rate with Delta - I'm not that convinced personally myself yet.

"I think one of the problems with these very common symptoms is they are quite difficult to convincingly link to the infection.

"But I think the key message is that people are being tested without symptoms and that's because we know this infection causes asymptomatic disease quite commonly and a lot of our testing now is being done in asymptomatic people with lateral flow tests etcetera.

"So I don't think there is any evidence that we are missing cases more with this variant than the other variants that preceded it."

Dr Ramsay also said she expects the vaccines to continue working against the new "Delta plus" variant and said officials are "on top of the situation".

"We are obviously around those cases we will do enhanced testing and enhanced follow-ups," she said.

"The good message is that what we expected to happen with Delta was that the vaccines would prove to still work against the more serious disease and we expect the same for this other variant.

"There is also the option of having different vaccine in the future and that is something we will have to continue monitoring."