Covid vaccines may need updating to protect against new variant, study suggests

Neutralising ability of antibodies typically falls eight-fold with South African variant

Coronavirus vaccines may need to be redesigned this year to boost protection against a new variant that emerged rapidly in South Africa, research suggests, while past Covid sufferers may not be protected against reinfection.

Research by South African government scientists reveals that mutations of the new variant, known as 501Y.v2 or B1351, make the variant substantially resistant to antibodies in blood plasma donated by Covid patients.

The findings suggest it may be more likely to reinfect people who have already had Covid, and that vaccines being rolled out across the globe may be less effective. Since the variant emerged late last year, it has prompted travel bans around the world.

The researchers found that the ability of antibodies to neutralise the virus typically fell eight-fold with the new variant, meaning that in lab tests eight times as much antibody was needed to disable the B1351 variant than older ones.

In work that has yet to be peer-reviewed, the team at the National Institute for Communicable Diseases in Johannesburg found that the potency of antibody-rich plasma varied widely.

The neutralising ability of plasma from some patients fell a staggering 64-fold when tested against the new variant, while for others the ability to wipe out the new variant was unaffected. Nearly half, or 21 of 44 patients, “had no detectable neutralisation activity”, the scientists write.

The researchers warn that the new variant poses a “significant reinfection risk” and highlights the “urgent requirement” for vaccines that can be rapidly redesigned. Cases of reinfection with the B1351 variant have already been reported in South Africa.

An eight-fold drop in neutralisation is the threshold the World Health Organization uses to decide when updates are needed for seasonal influenza vaccines, though the two infections are not directly comparable.

If the results from South Africa are confirmed, the risk of the variant spreading more widely would justify planning for a “potential strain update” this autumn, said Trevor Bedford, who works on immunology and virus evolution at the University of Washington.

“I’ll be getting the vaccine as soon as I’m able,” he tweeted. “We have an amazing vaccine now that works against currently circulating viruses. And if it becomes necessary, this emerging situation can be dealt with through a forthcoming vaccine update.”

The B1351 variant first found in South Africa is different from the B117 variant first spotted in Kent in September, though the two share a mutation in the spike protein which appears to make both more transmissible. The UK has recorded at least 29 cases of infection with the B1351 variant.

Danny Altmann, professor of immunology at Imperial College London, said the latest results were “disturbing” and could impact vaccines. “You need to pose the hypothetical question: are these effects big enough to subvert protection by the current vaccines? My current prediction is that, faced with the South African mutation, though probably not for B1.1.7, the answer would be yes,” he said.

Prof James Naismith, professor of structural biology at Oxford University, said the findings were “not good news”, but urged people not to panic. “The real world human immune response is more than serum-based neutralisation. Of course we would rather neutralisation had occurred but this does not mean that the new virus will infect, make ill and spread from those who have already been infected with the original strain,” he said.

Meanwhile, further research suggests the Pfizer/BioNTech vaccine does protect against the B117 variant blamed for the rapid rise in cases in London and south-east England.

Scientists at BioNTech tested the ability of antibodies drawn from 16 vaccine trial participants to neutralise viruses carrying either the spike protein from the original Wuhan variant, or one carrying the same mutations as the B117 variant. There was no difference between them, suggesting the vaccine should be equally effective against both variants.

“The news should not be considered surprising, but is very welcome. It will be interesting to carry out the same experiments with the South African variant,” said Dr Jonathan Stoye, a virologist at the Francis Crick Institute.

Even so, further research is needed, said Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading. “While this study confirms that the antibody response is not blunted by the mutations in this variant, it does not assess the effect that these may have on T-cell immunity, so it remains entirely possible that they could indeed have an adverse effect on vaccine-induced immunity,” he said.


Ian Sample and Linda Geddes

The GuardianTramp

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