Covid-19: what if France avoided a fifth wave? Reassuring news from epidemiologists – franceinfo

“You want to talk about the epidemic ? But it’s still a hot topic ? “ When we call him to inquire about the circulation of Covid-19 in France, epidemiologist Renaud Piarroux begins by responding in a tone of humor. As we enter the autumn season, the very one during which the second wave overwhelmed France a year ago, scientists are rather smiling. The significant drop in the number of cases in recent weeks and the high vaccination rates in the adult population make specialists optimistic for the coming months. But they also warn that the epidemic is not over yet.

With a number of contaminations per day down to around 5 000 and new daily hospitalizations also down – less than 300 patients per day on average since last week -, the indicators seem green. “The epidemic is decreasing with a reproduction number between 0.8 and 0.9. In other words, 10 people infect less than 9. The virus therefore continues to circulate but we are in a favorable situation. Last year at the same period, the number of reproduction was between 1.1 and 1.3, at the start of the second wave, which is not currently the case “, explains epidemiologist Mircea Sofonea.

For this researcher from the University of Montpellier (Hérault), whose job is to model scenarios on the future of the epidemic, we could even afford to receive a possible rebound this fall. “It is quite possible that the curves will stagnate, or even start to rise again in the coming weeks, thanks to the return of the cold and the shorter days. But the change of regime will not happen overnight. the following day”, he says.

“For the situation to be reversed, a new variant would be needed or there would be a sudden change in the application of barrier gestures. However, in the current state of knowledge, there is no threatening variant. in the process of replacing the Delta and we are not in the optics of a general relaxation of sanitary measures either. “

Mircea Sofonea, epidemiologist

Franceinfo

Even the start of the school year, which had nevertheless been concentrating concerns since the beginning of September, did not have the dreaded effect. “It’s been a month since the start of the school year. The Covid-19 has indeed been transmitted between children. But not that much in the end. Contaminations are decreasing even among those under 10, who are not however vaccinated”, notes Renaud Piarroux, head of the parasitology service at the Parisian hospital of Pitié-Salpêtrière.

According to the researchers, this thinning after nearly a year and a half of pandemic is explained above all by vaccination. “Last year, the second wave was the consequence of a relaxation initiated during the summer. What has changed this year is the vaccination”, explains Mircea Sofonea. According to the latest figures published by Public Health France, more than 88% of French people aged 18 and over have received at least one dose of the vaccine against Covid-19. And nearly 86% have a full immunization schedule. “The population’s immunity is pretty good”, also notes Renaud Piarroux. But it also alerts: “The challenge now is to maintain this immunity.”

Because as time passes, the hope of an outright disappearance of Covid-19 vanishes. “Vaccines are not as effective against infection and secondary transmissions as against severe forms of the disease. The idea that one could one day achieve herd immunity by this means alone is a pipe dream.”, warns the modeler Mircea Sofonea. According to this researcher, we are moving towards the scenario of endemic circulation, “That is to say influenza-like, with seasonality induced by the weather and the length of the day, a health impact of Covid-19 more or less important depending on the year and vaccines that may need to be updated”.

In the medium term, Renaud Piarroux says for his part that the injection of a booster dose to all people already vaccinated is necessary. “It is the vaccination that protects us. We know that two doses are not enough”, says this field epidemiologist. The researcher cites the case of Israel, a country which vaccinated its population very early on, as early as December 2020, but which despite everything experienced a new epidemic outbreak this summer. “We must start with the elderly and the most fragile. But if we do not want to let the virus take over, eventually, the entire population will have to be injected a third dose”, he warns.