Oxford scientists working on new Covid vaccine to target Delta variant


A new and modified version of the Oxford vaccine is being developed to target the Delta coronavirus variant, The Independent understands, in the wake of rising infections in the UK and the highest daily death toll since March.

Early work has been started by members of Professor Dame Sarah Gilbert’s team at the University of Oxford – the same scientists behind the AstraZeneca jab first rolled out in January. A source said the new vaccine was being designed with the aim of “having something on the shelf ready to scale up – if it’s needed”.

This comes as scientists warned that a new offshoot of the Delta variant will “eventually dominate” in the UK if it is confirmed to be more transmissible than its predecessor, with authorities now racing to better understand the newly mutated virus.

Downing Street has said it is keeping “a very close eye” on the AY.4.2 sub-variant, which is steadily spreading throughout England and accounted for nearly 10 per cent of new infections at the start of October.

Experts have speculated that it could be 10 to 15 per cent more transmissible than the original Delta variant.

The Covid-19 Genomics UK Consortium (COG-UK), which tracks new variants, said AY.4.2 “is likely to become dominant” in Britain if it is found to be more infectious. However, it said there is no evidence to support this yet, with tests under way to determine its “biological properties”.

Aris Katzourakis, a professor of evolution and genomics at Oxford University, said if the 10 to 15 per cent figure “holds up to scrutiny”, then AY.4.2 “will eventually dominate”.

Despite fears of its increased transmissibility, scientists do not believe the new Delta sub-variant is responsible for the recent spike in cases that have been reported across the UK.

Some 43,738 tested positive for Covid on Tuesday – down from almost 50,000 the day before – while a further 223 deaths were recorded, the highest figure since 9 March.

“As AY.4.2 is still at fairly low frequency, a 10 per cent increase [in] its transmissibility could have caused only a small number of additional cases,” said Professor Francois Balloux, director of the Genetics Institute at University College London. “As such it hasn’t been driving the recent increase in case numbers in the UK.”

Experts have meanwhile argued “there is a case” for Delta-specific vaccines for current and future vaccination programmes, with the variant now accounting for the vast majority of global infections.

Professor Eleanor Riley, an immunologist at Edinburgh University, said the biggest advantage would be to help bring widespread transmission in the UK “to an end”.

She said the UK’s autumn booster programme, which will ultimately see 30 million Britons offered a third vaccine dose, “would likely have much greater impact if we were using a Delta-specific vaccine”.

Given the continuing effectiveness of the original vaccine in protecting against hospitalisation and death from Covid-19, scientists at Oxford are taking a precautionary approach to developing a Delta jab.

The Oxford source said it was “very early days” in the development of the new vaccine, but insisted it wouldn’t be hard to make the necessary modifications given the “plug and play” nature of the technology behind the jab.

However, the source said that even “subtle changes” introduced to the manufacturing process as a result of switching to a modified vaccine could cause significant delays and hinder the global rollout of life-saving doses, at a time when millions of people remain unvaccinated.

Professor Riley said the protection afforded by the current vaccines against severe disease and death seems to be broadly similar for all variants.

“Those of us who have been vaccinated already are no more likely to end up in hospital with the Delta variant than with the original Wuhan or Alpha strains,” she said.

However, Prof Riley said that immunity against infection – “and thus the subsequent likelihood of transmitting the virus to someone else” – is affected by the different variants, with the Oxford jab not quite as effective in preventing vaccinated people from catching Delta and “feeling a bit unwell”.

“There is therefore a case for rolling out Delta-specific vaccines,” Prof Riley said. “They are likely to be significantly better at suppressing infections in the community and may well bring widespread transmission in the UK to an end.

“This, in turn, will reduce the number of unprotected (unvaccinated or unresponsive) people being infected and ending up in hospital.”

Pfizer has already announced its plans to develop a Covid booster shot that will target Delta, while Moderna has said it would be able to easily update its vaccine to take into consideration new variants. A timeframe for the new Oxford vaccine has not been released.

Professor Robin, an immunologist at Imperial College London, said “it certainly makes sense to introduce Delta-specific vaccines” and admitted he was “surprised” there hadn’t been a desire to roll out modified jabs as part of the UK’s booster campaign.

Prof Riley said periodic updated boosters might be required in the months or years to come if Sars-CoV-2, the virus that causes Covid-19, continues to “throw up new highly infectious variants”.

Prior to their work on Delta, scientists at Oxford developed a vaccine specific to the Beta variant, which has since dropped out of circulation in many countries of the world.

A University of Oxford spokesperson said: “Oxford has a broad programme of research on vaccines for coronaviruses and is monitoring emerging variants closely.

“We are working with our partners AstraZeneca on testing a Beta variant vaccine in human volunteers at the moment, and on the developing systems for evaluation and licensure of new variant vaccine, should it be needed.”

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