“This fifth wave may be the last.” The Minister of Health, Olivier Véran, allowed himself a note of optimism in the middle of a very gloomy news, Monday, January 3, on France Inter. According to him, the Omicron variant is so contagious that it “will lead to enhanced immunity” in the world and we will be “all more armed after his passage “. Before Olivier Véran, Professor Alain Fischer, the government’s “vaccine man”, had already estimated on BFMTV that the new variant was “a little more transmissible but less aggressive” and that we were assisting “at the beginning of evolution towards a more banal virus as we know of others”.
“The optimistic scenario is only a scenario, it is that of this double vaccine and natural immunity which will probably be acquired very quickly at the end of this blast. [explosion de contaminations]“, continues infectious disease specialist Benjamin Davido on franceinfo. “We can hope that the year 2022 will bring us this collective immunity so hoped for in 2020.” This is also the opinion of virologist Bruno Lina, also a member of the Scientific Council: “All people will be exposed to the virus, either in the context of vaccination and they will either make a minor infection or no infection, either without being vaccinated and they will get an infection. “
“We switch to a virus that gives more upper airway infections” and “go down less” in the lower lanes, adds Bruno Lina. This would pave the way for an influenza scenario, a seasonal illness that puts more limited pressure on the health system. “Ultimately, there is hope” and “Sars-CoV-2 will join other human seasonal coronaviruses that give us colds and tonsillitis every winter”, commented the epidemiologist Arnaud Fontanet in Sunday Newspaper.
“I still have hope that the virus will eventually look more like other cold coronaviruses – maybe within the next one or two years.”British virologist Julian Tang recently said, quoted by Science Media Center (in English). And this, “repeating the vaccines and keeping the mask and social distancing for the most vulnerable, like what we do for the flu every year”.
While the prospect of improvement remains open, “you have to be very careful” using the reading grid of Olivier Véran, nuance Jean-François Saluzzo, virologist and expert at the WHO. “It is a political statement but in my opinion we are far from the answer.” Asked by franceinfo, the researcher nonetheless identifies some encouraging signs: “The intense circulation of Omicron will nevertheless participate in community immunity. When you have an entire population vaccinated or already infected, the virus circulates less easily, even if it circulates anyway.”
“In France, the strong vaccination coverage and the previous contaminations did not constitute a barrier to contamination at Omicron. On the other hand, it created a barrier to serious clinical forms.”
Jean-François Saluzzo, virologistto franceinfo
The intense circulation of the virus “makes it clear that the outbreak will be short-lived”, adds Jean-François Saluzzo. “When most people have had it, the virus stops because it has little reservoir of population left to contaminate.” But the virus, he adds, will continue to circulate. It remains to be seen how. “In the spring, there is a risk of circulating quietly, and there we could be in an endemic and seasonal situation, especially in winter.” Sars-CoV-2, moreover, can continue to evolve, “the worst scenario being that in heavily vaccinated countries, a variant appears which completely escapes the immune system”.
At the start of the pandemic, collective immunity was for a time brandished as the end goal to turn the page on Covid-19 – there was sometimes talk of a threshold of 80% of vaccinated to put an end to the virus. But the relevance of this concept, resulting from veterinary efforts to manage epizootics, is the subject of debate within the framework of a human population, more mobile than the herds. Timidly mentioned at the beginning of the year 2021, with the deadline the following summer, it has in reality never been reached. “It is true that perhaps attaching to this collective immunity (…) is like a mirage every time”, lamented in September the virologist Samira Fafi-Kremer, interviewed by franceinfo.
To date, it therefore seems premature to imagine the post-Omicron period, if only because the evolutionary dynamics of the virus are, by nature, difficult to know. “Who can seriously say that there will not be a new variant that is more dangerous and that escapes the vaccine or post-infectious or vaccine immunity of the previous variants?” asks Gilles Deray, for example, head of the nephrology service at Pitié-Salpêtrière, in the columns of The Express. “For the first time, a variant significantly escapes vaccine immunity in the absence of a booster dose. If it happens once, it is not aberrant to think that it will happen again in the future”, confirms Samuel Alizon, research director at the Center for Interdisciplinary Research in Biology (CNRS-Inserm), to franceinfo.
In the background, many specialists, as well as the Minister of Health, are betting on a future evolution of the virus towards less virulent forms. But Samuel Alizon calls for caution on this point: one should not confuse, according to him, the number of deaths – which can vary according to the immunity in a population – and the intrinsic dangerousness of the virus – which exposes the individuals without no immunity. “What has often been taken for a decrease in virulence in many past epidemics is in fact only an increase in the immunization of populations”, explained the specialist in the modeling of infectious diseases, interviewed in mid-December by the Reporterre site.
Other parameters must be taken into account, such as the duration of protection acquired by vaccination or the potential cohabitation of variants – thus, will the Delta variant continue to perform resuscitations for a long time? “We must pass the double course of this double infection which is cumulative”, summarizes Alain Fischer on BFMTV. One way to focus on the current episode, and on the need for a large vaccination, before perhaps glimpsing a clearer sky. “I am convinced that it will not be the last wave”, thus declared to Parisian Eric Caumes, head of the infectious diseases department at Pitié-Salpêtrière. “But it might be the last of this intensity.”
In any case, France is not the only country to debate the sequence of events. In Israel, another country with high immunization coverage, senior public health adviser Nachman Ash ruled on Sunday that he was “possible” achieve herd immunity – preferably through broad vaccination rather than infection. Two days later, Salman Zarka, responsible for the fight against Covid-19, replied scathingly: “L’group immunity has no scientific basis. “