The Covid vaccine developed by the University of Oxford and AstraZeneca is nearly as effective against the Kent variant as it is against older forms of the virus, according to preliminary research results. Researchers analysed swabs from trial volunteers who developed asymptomatic or symptomatic infections to determine which variant of the virus they had caught after receiving the vaccine or a control jab. In a preprint under review at the Lancet, the scientists reported that levels of neutralising antibodies – those that wipe out the virus – were nine times lower in vaccinated people who caught the Kent variant, named B117, compared with those who contracted older variants. But the reduced antibody response was associated with only slightly lower protection against symptomatic infections with the Kent variant, the scientists said. Among the small number of people included in the study, vaccine efficacy fell from an average of 84% against older variants to 75% against the Kent variant. Despite the fall, the protection against what is now the dominant variant in the UK remains substantially above the 50% threshold the World Health Organization set as the pandemic took hold. The latest results are drawn from swabs taken between 1 October 2020, about two weeks after the first known case of B117 infection was detected in Kent, and 14 January. By that time the more transmissible variant had spread rapidly from Kent, London and the east across the rest of the country. The findings are the first to examine how well the Oxford vaccine, known as ChAdOx1, protects against the variant, which is one of a number of mutated forms of the virus causing concern around the world. B117 is about 50% more transmissible and perhaps 30% more deadly than older variants, though work is ongoing to confirm its lethality. Of more concern are new variants first discovered in South Africa and Brazil, which both bear a mutation called E484K. Early studies suggest the mutation may help the virus to evade immunity induced by vaccines and past Covid infection. The E484K mutation recently appeared among B117 variants, prompting fears the virus could become harder to control. Andrew Pollard, a professor of paediatric infection and immunity, and chief investigator on the Oxford vaccine trial, said: “Over the last couple of months we’ve seen very similar efficacy of the Oxford AstraZeneca vaccine against the B117, UK, or Kent variant, very similar to the original virus that was circulating last year.” The data is preliminary and involves swabs from only 499 trial volunteers. Of 1,524 positive nose and throat swabs collected from the participants, 323 swabs from 256 people yielded virus that was identified by genetic sequencing. Further analysis revealed that those who received the Oxford jab but still became infected shed the virus for a shorter time and had lower viral loads than those in the control group. The findings may help to explain why the vaccine appears to reduce transmission by as much as two-thirds after the first shot. Danny Altmann, a professor of immunology at Imperial College London, said the findings were positive. “By any standards this is very good news as the B117 variant with its increased transmission had the potential to derail our planned timeline for recovery. “This variant has been thought of as mainly facilitating transmission rather than evasion of immunity – the prediction from antibody neutralisation tests in the lab had been that the vaccine would still be protective. However, there’s a big gap between showing this in the lab and showing actual protection in the population. We still need to worry about the other variants with the E484K mutation, as in the South Africa variant and the new mutation in the UK. That’s the one where we really need a keen eye on how well the vaccines work,” he said. Sarah Gilbert, a professor of vaccinology and chief investigator on the Oxford vaccine trial, said the team’s platform technology allowed them to quickly update the vaccine to target new variants should that become necessary. “We don’t expect to go through the full process of clinical trials again,” she said. “We will be talking to regulators about the exact procedure that we’re going to be going through for using these updated vaccines, but there’s precedent from flu vaccines. This is done every year for flu vaccines.” The results came as the UK government announced a partnership with the vaccine manufacturer CureVac to rapidly develop vaccines against new variants. The government has placed an initial order for 50m mRNA vaccines from CureVac to be delivered later this year if needed. Almost all of the vaccines developed by the partnership will be versions of an existing jab CureVac has in phase 3 clinical trials.