Covid-19: the Delta variant now the majority in almost all of the departments, discover our map

As expected, it is gradually imposed.

More than half of the positive tests screened are now suspected of a Delta variant in the vast majority of metropolitan departments, according to the latest data from Public Health France.

By removing the territories where less than 30 positive tests were screened, the figures not being significant enough, only the Haute-Garonne, the Eure, the Pyrénées-Atlantiques, the Yonne, the Mayenne, the Allier and the Loiret have not yet crossed the 50% threshold.

The Delta variant also remains an ultra-minority overseas.

Read alsoCovid-19 and Delta variant: what the first study says on the vaccination status of positive people in France

These suspicions are established from the data of the screening, when the L425R mutation on the surface of the virus is detected.

This Delta variant, as we know, is very transmissible (between 40 and 60% more than the so-called “British” Alpha variant, previously in the majority).

And all the experts expect it to gradually become hegemonic in France, but also in Europe.

Incidence rate on the rise, especially among young people

In a model published on Tuesday, the Institut Pasteur anticipated that this strain would represent almost 100% of positive cases in each of the metropolitan areas at the end of July. “We were surprised to have such high growth rates for Delta, even if they are compatible with what we are seeing abroad. And we have a fairly similar signal in all regions, ”said the Parisian Simon Cauchemez, the head of the mathematical modeling unit of infectious diseases at the Institut Pasteur.

What impact will this have on the epidemic?

Already, the incidence rate, that is to say the number of positive cases per 100,000 inhabitants over the past week, is on the rise in almost all of the departments.

He more than tripled in 9 territories, but often from low level.

The Pyrénées-Orientales is the first metropolitan department to rise above 200 (five times more in a week).

One thing systematically emerges: like last summer in France, and like many of our neighbors, it is especially among adolescents and young adults that the incidence is climbing.

At the national level, it now reaches 132 among 20-29 year olds and 73 among 10-19 year olds.

"No strong correlation for the moment"

On the other hand, according to our analysis, no obvious correlation between the evolution of the incidence rate and the share of the Delta variant emerges at this stage.

“It's true that we don't see a strong correlation at the moment.

The change in incidence seems to be more in line with a relaxation of barrier measures and frequentation of places prone to contamination.

But what can be worrying is that in this context of viral circulation, when this Delta variant reaches a very high prevalence, it could be an aggravating factor, ”replied Friday, July 9, Guillaume Spaccaferri, epidemiologist at Public Health France.

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The positive cases being mainly young, this does not yet really have an impact on hospitalizations.

These have stagnated for two weeks and have risen slightly for several days, but it is too early to say if this will be confirmed in the short term because some departments posted figures that were probably overestimated at the start of the week.

Read also Delta variant: this is what the "fourth wave" could look like in the hospital

Despite everything, and even if the vaccination is progressing, a hospital wave at the end of the summer is not excluded.

“With 10% of elderly unvaccinated, this forms a sufficient reservoir to lead to many hospitalizations.

And we must also count those among younger unprotected adults, ”says Simon Cauchemez.