To date, it represents almost three quarters (73%) of cases in the United Kingdom. The so-called Indian variant, or Delta variant, worries the British health authorities, who publish on June 3 a full report on the subject.

According to the data available to date and analyzed in this report, the Delta variant is more transmissible and could be the cause of more severe forms of covid.

More contagious than the Alpha variant

Indeed, the Delta variant is gaining ground in the United Kingdom when the British variant, or Alpha variant, decreases. Which means that the Delta variant is “very probably“more transmissible than the Alpha variant. Which was itself between 50 and 70% more contagious than the historic strain.

More hospitalizations?

But that’s not all. According to two studies conducted in England and Scotland relayed by Public Health England, the risk of hospitalization is increased with this Delta variant compared to the Alpha variant. A warning signal, even if further analyzes are necessary to confirm this fear.

Another open question: that of the risk of reinfection. The data available to date do not yet allow to know whether the Delta variant can cause a new infection in people cured of a covid linked to another variant.

Vaccines remain effective

The health authorities, however, issue a note of hope: the majority of positive cases for the Delta variant, hospitalized and deceased because of this variant had not been vaccinated, or had received only one of the two doses.

This suggests that anti-covid vaccines offer protection against this variant or the serious forms it causes. Provided that both doses have been administered.

No precise figure in France

And in France, what is the situation? We do not have “no idea“the precise number of cases of Delta variant in the territory, warns Professor Philippe Froguel geneticist at the University Hospital of Lille.

The reason: the absence of screening tests – which make it possible to roughly recognize one strain compared to another – and the considerable drop in the number of sequencing of the genome of viruses – which make it possible to precisely identify a variant – carried out in France.

The only count made is that of Inserm flash surveys, “performed every two or three weeks and which require three weeks to publish results“, observes the scientist.

A risk of loss of control

The risk ? A loss of control of the situation and a rapid increase in cases linked to a variant, as was the case with the British variant Alpha in early 2021, recalls Philippe Froguel.

This is for example what happened in Dax, “where the Indian variant was identified one month after the patient’s diagnosis “ he laments. In summary, “we have no real way of detecting the Indian variant, but neither the Vietnamese variant or any new variant “ he still worries.

Vaccinate faster than the advance of the variant

What development can then be expected on French territory? “I’m not saying it’s gonna be a disaster, I’m just saying we’re sailing with our eyes closed“answers the geneticist.

The question is not whether the Indian variant will develop, there is nothing to discuss. But it is necessary to delay its development sufficiently so that three quarters of the population is fully vaccinated, with two doses “ he finally advances.