South African variant of Covid could affect vaccine effectiveness, scientists warn

The new variant of the coronavirus linked to an increase in the number of Covid-19 cases in South Africa is not only more infectious than previous forms of the virus, but could make some vaccines less effective.

Scientists rushing to understand the new strain said they still expected the current crop of approved vaccines to work, but worried that a specific mutation, also identified in a new variant in Brazil, could affect the way to which the virus responds.

“Right now we think a vaccine might be a little less effective,” said Professor Tulio de Oliveira, University of KwaZulu-Natal, who is leading the South African scientific effort to understand strain 501Y. .V2, at the Financial Times. . “[But] among all the varieties of vaccines that are coming to the market, we are still convinced that some of them will be very effective. “

The mutation in question, called E484K, changes the “receptor binding domain” – a key part of the spike protein that the virus uses to enter human cells. It is also an important site where neutralizing antibodies induced by infection or vaccination bind to the virus.

A team from the Fred Hutchinson Cancer Research Center in Seattle evaluated the ability of antibodies taken from people previously infected with Sars-Cov-2 to neutralize various new strains of coronavirus.

Their study, published Tuesday but not peer reviewed, found that “emerging lines in South Africa and Brazil carrying the E484K mutation will have significantly reduced susceptibility to neutralization. . . serum antibodies of certain individuals ”. However, the effect was much stronger in some people than in others, according to the newspaper.

Professor de Oliveira’s team in South Africa came to similar conclusions. “This discovery on antibody neutralization was highlighted very strongly in our article,” he said. “There is a reason to be concerned.”

Professor de Oliveira added that his team had spent “the last 15 days, working day and night, with the best laboratories in South Africa” ​​and would soon publish “strong preliminary results”.

The 501Y.V2 variant appeared in August in Nelson Mandela Bay, South Africa, in the Eastern Cape, before spreading to other provinces as the country’s second wave of Covid-19 infections took hold. has accelerated in recent weeks. Out of 1.1 million confirmed cases in South Africa to date, around 100,000 have been confirmed in the past seven days.

Variants of the coronavirus are emerging around the world as Sars-Cov-2 passes between tens of millions of people. On average, the virus accumulates around two mutations per month, but it can change more quickly under certain circumstances – for example, in an individual who has a weakened immune system and remains infected for several weeks.

The South African and Brazilian strains share several mutations with the rapidly spreading B.1.1.7 variant in the UK, which made its first known appearance in Kent in late September. But B.1.1.7 does not have the E484K mutation.

For this reason, “most scientists with a view on these variants are more concerned with South Africa than Kent,” said Francois Balloux, director of University College London Genetics Institute.

Matt Hancock, Britain’s Health Secretary, has repeatedly expressed concerns about the South African variant, saying on Monday he was “incredibly worried”.

Professor de Oliveira called Mr Hancock’s comments, which were seen by some in South Africa as an attempt to distract from the UK, “very unfortunate”.

“We are really doing our best to see if this politicization can decrease,” he said. “We are working closely with British scientists. We exchange data and knowledge almost daily on the scientific front. Our job as a global scientific community is to try to defuse this kind of tension.

The UK and South Africa – unlike most other countries – have carried out extensive genomic sequencing throughout the pandemic, allowing health officials to quickly track mutations. This could mean that other, more infectious variants are already spreading to other countries undetected.

So far, no new variant of Sars-Cov-2 is known to cause more severe disease than the original virus that emerged in China at the end of 2019, but faster transmission rates have exercised greater pressure on hospitals and health systems.

“The main take-home message is that we shouldn’t play with this virus by letting it spread for so long,” said Professor de Oliveira. “More than ever, this is a global problem and we should seek a global coalition to address it.”