This is a figure that had not been reached since the beginning of April 2022 with the Omicron BA.2 sub-variant. The number of Covid-19 contaminations amounts to more than 206,000 over the last 24 hours, according to data from Public Health France published this Tuesday evening July 5.

The seventh wave of the epidemic, which started at the end of May 2022 in France, in the wake of South Africa and Portugal, “has been increasing in recent days” and “we are recording around 120,000 cases (per day) on average over the past week, with a number of cases which should slightly exceed 200,000 this evening”, declared the new Minister of Health François Braun at the start of a discussion on the bill “of monitoring and health security”, during a hearing at the National Assembly.

When will the peak of this seventh wave carried by the BA.5 sub-variant occur? On RTL, June 30, the president of the scientific council Jean-François Delfraissy placed it at “end of July”. This new wave should “not spoil the summer because we are vaccinated”, he estimated, specifying however that the care system could be under tension again towards the end of July.

Since the arrival of the Omicron variant, it has become increasingly difficult to anticipate waves, the peaks of these waves and their impact on the hospital system. “The modellers are tearing their hair out”, reports to L’Express Bruno Lina, professor of virology at the Lyon University Hospital and member of the Scientific Council, evoking a “complex panorama, which will become more and more so” at the coming. He explains: “We are having a lot of trouble defining a method of calculation that is robust enough to allow us to have certainties. When the virus appeared, it was simpler to make a model: there is no had no immunity then and we knew what the impacts of the various measures to curb transmission were.

Now, with the particularly contagious BA.5 sub-variant, “the elements driving this epidemic are multifactorial”, such as the characteristics of the new Omicron sub-variants, the share of the population having already had Covid-19, the coverage vaccination, the decline in the effectiveness of vaccines over time… “Several factors are intertwined such as post-infectious immunity, post-vaccination immunity and immune escape (Editor’s note: the lower effectiveness of the protection vaccinated people, or people who have already been sick with certain viral strains)”, notes Bruno Lina, adding that this “complexity” is however not new and also applies to other epidemics, such as the flu.

The virologist specifies that vaccination is “only one element to take into account” and that it is “insufficient”. This factor intervenes “marginally” when developing a model assessing the dynamics of the epidemic, unlike a prior infection. In addition, other elements have an impact on the evolution of the epidemic, such as compliance with barrier measures, particularly hand hygiene and the wearing of masks. These gestures “keep their effectiveness but are perceived as constraints” at a time of weariness of the population, notes the virologist.

These many parameters to be taken into account to measure the evolution of the epidemic now leave the health authorities in the dark. “It is difficult to know what the impact will be in France in terms of hospitalizations and deaths of the BA.4 / BA.5 epidemic wave which is beginning”, notes the Scientific Council in its analysis of the wave and the “watchdog” bill. and health security”, transmitted to the government on June 23 but made public on Monday July 4.

For Bruno Lina, “it is very unlikely that the impact of this wave will be massive in terms of deaths and hospitalizations”. However, “it will not be trivial either because a group of people may present a risk of serious infection, except in the event of a booster vaccination: people over the age of 80 and those over 60 with comorbidity factors”. Hence the need for these people at risk to receive a first or second booster shot, insists the member of the Scientific Council, in line with the message hammered home by the government for several days. “The situation in the hospital is not good, the system is strained. If these people do not get vaccinated, it will have consequences for everyone. The preservation of our health system this summer goes through this vaccination reminder” , he points out.

If he “does not know how to say” when the peak of this seventh wave will occur, Bruno Lina notes that several indicators closely scrutinized by scientists can encourage optimism for the future, such as the positivity rate which “is going through a peak” and the incidence rate which “peaks out a bit”. After this peak, Jean-François Delfraissy estimates for his part that “new variants will appear in the fall. The problem is to know if we will still have BA.5 in the fall, or if there will be yet another variant “.

The Scientific Council does not say anything else in its opinion of June 23: “Whether it is a question of the continuation of the ‘optimization’ of Omicron by successive mutations giving rise to sub-variants better and better adapted to humans, or the occurrence of a new variant of concern (VOC) via already known emergence processes (chronic SARS-CoV-2 infections in immunocompromised people, recombination, or retro-zoonosis), it is necessary to s expect new epidemic waves of Covid-19.” The time when the former Minister of Health, Olivier Véran, who estimated at the beginning of January 2022 that it would be “perhaps the last variant, perhaps the last wave”, seems more and more distant.