The new variant of coronavirus associated with an increase in Covid-19 cases in South Africa is not only more infectious than previous forms of the virus, but may make some vaccines less effective.
Scientists who are trying to understand the new strain said they still hope that the current crop of approved vaccines will work, but fear that a specific mutation, also identified in a new variant in Brazil, may affect the way the virus responds.
“At the moment, we think that a vaccine could be a little less effective,” Professor Túlio de Oliveira, from the University of KwaZulu-Natal, who leads South Africa’s scientific effort to understand the 501Y.V2 strain, told the Financial Times. “[But] among all the varieties of vaccines that are reaching the market, we still strongly believe 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. This is also an important location where neutralizing antibodies induced by infection or vaccination bind to the virus.
A team at the Fred Hutchinson Cancer Research Center in Seattle evaluated the ability of antibodies taken from people previously infected with Sars-Cov-2 to neutralize several new strains of coronavirus.
The study, released on Tuesday but not peer-reviewed, found that “emerging strains in South Africa and Brazil that carry the E484K mutation will have a very low susceptibility to neutralization by. . serum antibodies of some individuals ”. However, the effect was much stronger in some people than in others, the newspaper said.
Prof de Oliveira’s team in South Africa came to similar conclusions. “This discovery about antibody neutralization was highlighted strongly in our article,” he said. “There is a reason to be concerned.”
Professor de Oliveira added that his team spent “the last 15 days, working day and night, with the main laboratories in South Africa” and would soon release “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 has accelerated in recent weeks. Of the total 1.1 million confirmed cases in South Africa to date, about 100,000 have occurred in the past seven days.
Variants of the coronavirus are emerging worldwide as Sars-Cov-2 passes through tens of millions of people. On average, the virus accumulates about two mutations per month, but it can change more quickly in some circumstances – for example, in an individual who has a suppressed immune system and remains infected for many weeks.
The South African and Brazilian strains share several mutations with the rapidly spreading variant B.1.1.7 in the United Kingdom, which made its first known appearance in Kent in late September. But B.1.1.7 does not have the E484K mutation.
For that reason, “most scientists with a vision of these variants are more concerned with the South African than with Kent,” said François Balloux, director of the University College London Genetics Institute.
Matt Hancock, the UK health secretary, has expressed concern about the South African variant on several occasions, saying on Monday that he was “extremely concerned”.
Oliveira’s professor described Mr. Hancock’s comments, which were perceived by some in South Africa as an attempt to divert attention from the UK, as “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 in the scientific area. Our job as a global scientific community is to try to ease that kind of tension. “
The United Kingdom and South Africa – unlike most other countries – carried out extensive genomic sequencing during the pandemic, allowing health officials to track mutations quickly. This could mean that other, more infectious variants are already spreading in other countries undetected.
To date, no new variant of Sars-Cov-2 is known to cause more serious illnesses than the original virus that emerged in China in late 2019, but faster transmission rates have increased pressure on hospitals and healthcare systems.
“The main message to take home is that we shouldn’t play with this virus and let it transmit for so long,” said Professor de Oliveira. “More than ever, this is a global problem and we must look for a global coalition to respond.”