While all eyes are on the Delta variant (called "Indian"), others are just as worrying.
And in particular those bearing the E484K mutation.
There are ten of them, three of which are classified as "worrying": the famous Beta (known as "South African"), Gamma ("Brazilian"), as well as 20I / 484K, a derivative of Alpha ("British") which acquired the famous E484K mutation.
Delta is not on this list.
All included, these ten variants of SARS-CoV-2 went in two months from less than 6% to 14% of the samples sequenced during the Flash surveys, carried out every two weeks.
20I / 484K "seems to be progressing the fastest, particularly in the Île-de-France and Hauts-de-France regions", indicates Public Health France in its latest weekly epidemiological bulletin.
Several clusters in the workplace and in hospitals are being investigated in the North, and "measures have been put in place in these structures to limit the spread of this variant".
Poor immune response
As a reminder, a variant is the result of several mutations. Schematically, the name given to this mutation, E484K, means that the 484th amino acid of the virus's Spike protein was changed when it replicated. If Public Health France says "follow with attention" this spread, it is because E484K could reduce the effectiveness of vaccines in the event of infection by a variant which sports it. People who have had the Covid in the past would also be less protected, as evidenced by the cases of reinfection by the Beta or Gamma variant which were identified at the beginning of 2021. It "is the most worrying of all" on the plan of the immune response, estimated as early as January Ravi Gupta, professor of microbiology at the University of Cambridge.
Several scientific works, including a study published in early April in "The Lancet Microbe", have confirmed these concerns. Today, "numerous in vitro data [that is to say carried out in the laboratory and not in real life, Editor's note]" raise fears of a decrease in the effectiveness of vaccines or post-infection immunity, indicate Public Health France and the National Reference Center for Respiratory Diseases of the Institut Pasteur in their latest risk analysis, published Friday evening. "It is obviously the only mutation capable of causing relative resistance to immunity without, moreover, disadvantaging the virus (either by reducing its contagiousness or by hindering its ability to multiply)", adds Stéphane Korsia-Meffre, medical editor for the Vidal.
Read also Covid-19: why the number of variants identified in the world is likely to multiply
This mutation will now be specifically "targeted" when screening for positive tests, just like E484Q and L452R.
This technique, “complementary” to sequencing, is not as precise as the latter because it does not make it possible to identify a variant as such.
But it has the great advantage of being much faster than the Flash surveys (the last whose results are known dates from ... May 11).
The goal: "to allow more reactive monitoring of the dissemination of variants carrying these mutations of interest at the national level and in the most affected territories".
And, as a result, intensify the “test, trace, isolate” in these areas in the event of an alert.
Towards a third dose of vaccine?
All is not necessarily dark, however.
“The virological and epidemiological data available to date suggest that none of these three mutations of interest [E484K, but also E484Q and L452R] is sufficient on its own to make a variant more competitive than other variants which do not carry these mutations ”, indicate the French health authorities.
This could explain why Alpha remains largely in the majority in all French regions.
“You need a set of anomalies to make a variant more competitive,” says geneticist Philippe Froguel.
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Pfizer and Moderna, the two producers of the messenger RNA vaccine administered in France, have already announced that they would be able to develop a product effective against all the strains in circulation. "The V2 of vaccines including these mutations should be fatal to the virus", anticipates Stéphane Korsia-Meffre. On May 5, Moderna shared optimistic first results from phase 2 of a clinical trial involving a third injection of its vaccine against variants. His boss, Stéphane Bancel, recommended at the end of May in the JDD to "vaccinate with a third dose all those at risk from the end of the summer". Nothing has been acted on at this stage by the government. "He is the manager of a biotechnology company, not of a scientific authority", proclaims the Ministry of Health.