New viral mutation raises questions about vaccines

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Paris (AFP)

While the UK variant of the coronavirus occupies countries’ pandemic plans due to its increased transmissibility, other Sars-CoV-2 mutations are causing concern among scientists as they work to determine if they will continue to respond vaccines.

In particular, a mutation, known as E484K, initially detected in South Africa and on later variants in Brazil and Japan, has raised alarm bells among researchers.

Ravi Gupta, professor of microbiology at the University of Cambridge, said that it is this mutation – and not the heavily covered UK variant – that is “the most disturbing of all”.

Although research on the new variant is limited, a Brazilian study this month examined a patient who had recovered from Covid-19 to be re-infected with the new mutated strain.

The article has not yet been peer reviewed, but the authors found that the E484K mutation could be “associated with the leakage of neutralizing antibodies” – meaning it could bypass the body’s natural defense memory. which confers immunity.

As countries speed up their vaccination programs, there are fears that the new mutation may make some vaccines less effective.

The Pfizer and Moderna vaccines, for example, use mRNA technology to instruct the body to produce a harmless coronavirus spike protein, which the immune system then learns to kill in anticipation of an actual infection.

With E484K, as with the British variant, the mutation occurs on the spike protein of the virus, which allows it to bind more easily to receptors in human cells, potentially increasing its infectivity.

Gupta said the mutation “could be the start of problems for advanced vaccines.”

“They should all be effective for now, but we are concerned about the occurrence of additional mutations,” he told AFP.

– ‘Branch current protection’ –

Pfizer and its German partner BioNTech said last week that their vaccine was effective against the N501Y mutation found on the variant of the British virus, known as B117.

Francois Balloux, professor of computer systems biology and director of the Institute of Genetics at University College London, said the South African variant was unlikely to have mutated enough to “bypass the protection provided by current vaccines ”.

But, he warned, “The E484K mutation has been shown to reduce antibody recognition.

“As such, it helps the Sars-CoV-2 virus bypass the immune protection provided by a previous infection or vaccination,” Balloux said.

There have been several mutations in the new coronavirus since it emerged in late 2019, and most have had a negligible effect on its transmissibility or severity.

But the British variant has been shown in several studies to be up to 70% more infectious than normal viral strains.

And the South African variant appears to be more effective at avoiding the body’s natural response.

– New vaccines? –

A preprinted study in December concluded that the two new variants show that Sars-CoV-2 “has the potential to evade an effective immune response.”

Researchers studied what happened to the virus when it was left in contact with plasma taken from a patient who had recovered from Covid-19.

In less than three months, the virus had taken on several mutations, including E484K.

The authors suggested that “vaccines and antibodies capable of controlling emerging variants should be developed.”

Lead researcher Rino Rappuoli, an immunologist at pharmaceutical giant GlaxoSmithKline, told AFP that current mutations in spike proteins should not be a problem for existing vaccines, however.

And even if the virus mutates to better evade the immune response, vaccines should confer at least some effective level of immunity.

“Even if you decrease the efficiency, there would normally still be some neutralization of the virus,” Vincent Enouf, of the Institut Pasteur in Paris, told AFP.

To be on the safe side, Gupta advocated an accelerated vaccination program, conferring as much immunity as current vaccines can be delivered “as quickly as possible anywhere in the world.”

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