It is the variant now in the majority in the United Kingdom, whose deconfinement plan it threatens: the “Delta” - thus renamed to no longer stigmatize India where it was identified in April. It is the cause of three out of four contaminations. And for a few days now, he has worried the French health authorities, whose attention is focused on the southwest, especially in the Landes, where there is an upsurge in Covid-19 cases. Since Wednesday, 31 contaminations have been attributed to "Delta", for about fifteen sources of contamination. The Regional Health Agency (ARS) of Nouvelle-Aquitaine said it had identified "about twenty other probable". What to call into question the deconfinement, at least locally?
Invited this Sunday of the program "BFM Politics", in partnership with Le Parisien-Today in France, the Minister of Health, Olivier Véran, wanted to be reassuring. The situation is "not at all the same as in Great Britain," he assures us. There is no extension of the epidemic but clusters ”, adding that there is“ no major concern ”at this stage. However, several points worry epidemiologists.
"With the reopening of restaurants, bars, more important brews of people that will take place on Wednesday, the southwest is, to a certain extent, becoming an area, if not at risk, where we must be extra vigilant. », Confirms Jonathan Roux, epidemiologist at the Rennes School of Public Health Studies.
Especially since, according to a British study, it is 40 times more contagious than English, itself 50 times more contaminating than the original strain of Covid-19.
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"It can therefore, as in the United Kingdom, develop at high speed if we relax the vigilance", continues the specialist.
Thus, last Wednesday, Gabriel Attal, the government spokesman, noted "warning signals" in several departments of Nouvelle-Aquitaine, in particular the Landes, Charente-Maritime, Lot-et-Garonne, but above all, the Pyrénées-Atlantiques, where the incidence rate has increased by almost 80% in one week.
"But these are departments that had so far been spared by the epidemic, the incidence rate was low there before these cases of Delta, so the increase seems spectacular", notes Jonathan Roux.
"If we test more, it is normal that there is a rising incidence rate", also recalled Olivier Véran.
"Generalized retro-tracing"
Paradoxically, the fact of having been an area little affected by the virus can also be a factor in the explosion of cases. "There is a little developed natural immunity, since few people have been sick," recalls Jonathan Roux. Vaccination takes place there without a hitch, at a rate that places even the southwest among the best vaccinated departments in France. “But we can imagine that the clusters identified concern young people. Admittedly, 24% of people in the Landes received their two doses. But there are still 75% of the inhabitants, ”adds the epidemiologist.
To track down this Delta variant and prevent its dissemination, "retro-tracing is generalized", indicated Alaa Ramdani, head of the testing-sequencing pole at ARS Paca, this Sunday at the JDD.
"We are no longer looking only for people in contact, but those who have infected it," he explains.
A "lacemaker's job" which requires investigators to go back up to 14 days before the contamination.
Fastidious, but the most effective weapon against a resumption of the epidemic.
"If we do not manage to curb this variant, we can fear localized restrictive measures", anticipates Jonathan Roux.
Which wouldn't surprise the locals.
“In recent weeks, we have seen an influx of tourists, restaurants have reopened, people are going out. It is difficult not to relax vigilance, underlines Cécile, a teacher in a school near Mont-de-Marsan. She herself was vaccinated, anticipating a possible epidemic rebound and wanting to "take all precautions" to avoid a closure of her school. “My class is 32 m2, there are 27 students and me. With this more contagious variant, it is a potential cluster. "