the virus variant discovered in Japan, a challenge for vaccines?

The announcement on Tuesday of the discovery in Japan of a new strain of SARS-CoV-2 worries the scientific community, because it has characteristics that may interfere with the effectiveness of vaccines already developed against Covid-19.

Each day suffices for his mutation of SARS-Cov-2. After a media-scientific runaway around the British variant, it is a new strain of the coronavirus identified in Japan that is holding the attention of the scientific community.

Japanese health authorities admitted Tuesday, January 12, to have discovered a brand new form of the virus in four infected patients who arrived from Brazil. Nothing extraordinary in itself: “There are mutations of SARS-CoV-2 all over the world all the time,” recalls Simon Clark, professor of cellular microbiology at the University of Reading, contacted by France 24. C ‘ It is in the nature of this type of virus, like that of the flu, to mutate when it replicates in an infected organism. And most of the time, these changes do not affect the dangerousness of the pathogen.

The E484K threat

So why did Ravi Gupta, one of Britain’s foremost microbiologists, call this new strain the “most disturbing variant” at the moment? His fear stems from the number and location of the mutations. The Japanese National Institute of Infectious Diseases has discovered twelve mutations in the “spike” protein, that is, the part of the virus “which it uses to come into contact with and attach to the cells of the infected organism. “, recalls Lawrence Young, virologist and professor of molecular oncology at Warwick Medical School, contacted by France 24.

It is these mutations that scientists fear the most because they can affect the transmissibility and resistance of the coronavirus to antibodies, underlines the British specialist.

In this case, if this new variant is just beginning to be studied, the scarce information provided by the Japanese authorities does not give cause for optimism.

This variant has in fact the same mutation identified in the British strain – called N501Y – which has helped to make it much more contagious. But to this is added another modification, already observed in the variant discovered in South Africa on January 6 and which had pushed the famous specialist in infectious diseases of the US administration Anthony Fauci to sound the alarm.

This new enemy in the fight against Covid-19 is called E484K. It’s a mutation that “changes the biochemistry and shape of the ‘spike’ protein,” says Simon Clark. Concretely, the scientists estimate that it allows the virus to “cling more firmly to the contaminated cells”, specifies Lawrence Young. A South African study further suggests that the subtle changes to the appearance of the “spike” protein make the antibodies, which the immune system produces to fight Covid-19, less effective. “They might have a harder time attaching themselves to the virus to fight it,” said Lawrence Young.

Vaccines suspended?

The new variant discovered in Japan thus resembles an explosive cocktail that would present the biggest challenge to date for vaccines against Covid-19. On the one hand, it is impossible to know whether these long-awaited remedies remain effective against a form of the virus which has twelve mutations in its “spike” protein (which is the target of vaccines). “It is estimated that the vaccine continues to do its job when there are three or four mutations in the ‘spike’ protein, but beyond that it becomes difficult to say,” Judge Lawrence Young. On the other hand, the fact that the E484K mutation makes it harder for antibodies produced after vaccination is not a good sign either.

But all this remains theoretical. “We have, for the moment, no concrete proof that this new strain defies the effectiveness of vaccines and it will be necessary to wait to know more before asking the pharmaceutical companies to get back to work”, assures Simon Clark, the microbiologist at the University of Reading. For him, it is also likely that in the worst case scenario, the effectiveness of the vaccines developed “would be reduced” and not reduced to nothing.

And if we still had to adapt the vaccines to this new strain, “that would not require starting from scratch,” says Lawrence Young. Much of the work to determine the best way to fight this virus has already been done and the British researcher believes that the development of new vaccines would not take more than a month or two. Importantly, the entire administrative certification and authorization process would be much faster, because “the clinical safety profile of the vaccines would remain the same,” notes Lawrence Young.

However, the discovery of this variant perfectly illustrates what, in the eyes of this British virologist, awaits the world. The vaccines developed are a crucial step in the fight against Covid-19, but it’s a safe bet “that they will have to be adapted from time to time to the emergence of certain mutant strains”, he concludes. After all, this is also what happens with the flu.

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