PARIS (AFP) – As the British coronavirus variant occupies countries’ pandemic plans due to its greater transmissibility, other mutations in Sars-CoV-2 are causing concern among scientists struggling to find out whether they will respond to vaccines.
In particular, a mutation, known as E484K, initially detected in South Africa and in subsequent variants in Brazil and Japan, has raised alarm among researchers.
Ravi Gupta, a professor of microbiology at the University of Cambridge, said it is this mutation – and not the well-known British variant – that is “the most worrying of all.”
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Although research on the new variant is limited, a Brazilian study this month looked at a patient who had recovered from COVID-19 only to be reinfected 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The article has not yet been peer-reviewed, but the authors found that the E484K mutation could be “associated with the escape of neutralizing antibodies” – meaning that it could bypass the body’s natural defense memory that confers immunity.
A patient with an oxygen mask is being treated in makeshift emergency units at Steve Biko Academic Hospital in Pretoria, South Africa, on January 11, 2021, as the country faces an increasing number of COVID-19 patients. (AP Photo / Themba Hadebe)
As countries accelerate their vaccination programs, there is concern that the new mutation could make some vaccines less effective.
The Pfizer and Moderna vaccine, for example, uses mRNA technology to instruct the body to produce a harmless coronavirus spike protein, which the immune system learns to kill before a genuine infection.
With the E484K, as with the British variant, the mutation occurs in the virus’s spike protein, which allows it to bind more easily to human cell receptors, potentially increasing their infectivity.
Gupta said the mutation “could be the start of problems for peak vaccines”.
“All of them should be effective at the moment, but we are concerned about the occurrence of new mutations beyond these,” he told AFP.
‘Bypass current protection’
Pfizer and German partner BioNTech said last week that their vaccine was effective against the N501Y mutation found in the British virus variant, known as B117.
François Balloux, professor of computer systems biology and director of the Institute of Genetics at University College London, said the South African variant is unlikely to have mutated enough to “ignore 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 to circumvent the immune protection provided by previous infection or vaccination,” said Balloux.
This 2020 electron microscope image from the National Institute of Allergy and Infectious Diseases shows a new Coronavirus SARS-CoV-2 particle isolated from a patient in a laboratory in Fort Detrick, Maryland. (NIAID / NIH via AP)
There have been several mutations in the new coronavirus since its appearance in late 2019, and most have had a negligible effect on its transmissibility or severity.
But the British variant has shown in several studies to be up to 70% more infectious than normal strains of the virus.
And the South African variant appears to be more effective in preventing the body’s natural response.
New vaccines?
A pre-printed study in December concluded that the two new variants show that Sars-CoV-2 “has the potential to escape an effective immune response”.
The researchers studied what happened to the virus when it was left in contact with plasma taken from a patient who recovered from COVID-19.
Within 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”.
A man receives a COVID-19 vaccine at the Clalit Covid-19 vaccination center in Jerusalem on December 24, 2020. (Yonatan Sindel / Flash90)
Principal investigator Rino Rappuoli, an immunologist at the pharmaceutical giant GlaxoSmithKline, told AFP that current peak protein mutations should not pose a problem for existing vaccines.
And even if the virus mutates to better prevent the immune response, vaccines must provide at least some level of effective immunity.
“Even if you decrease the effectiveness, there would normally still be some neutralization of the virus,” Vincent Enouf, of the Pasteur Institute in Paris, told AFP.
To be on the safe side, Gupta advocated an accelerated vaccination program, giving as much immunity as current vaccines can provide “as quickly as possible worldwide”.