The announcement may have come as a surprise, but it was expected to be a relief for populations vulnerable to respiratory infections. For them, the Covid-19 vaccination campaign has been brought forward to October 2, French Health Minister Aurélien Rousseau told Agence France-Presse on Friday, September 15. Until then, the date was October 17 for a coupled vaccine administration targeting Covid-19 and seasonal influenza in compliance with the French government's recommendations.

But the SARS-CoV-2 virus, thwarting these forecasts, decided otherwise. "I have just received Professor Brigitte Autran [the president of a health committee, COVARS], who provided me with a recommendation as of September 15 stipulating that vaccination be opened up more rapidly to fragile people more directly exposed to the virus," Rousseau said. "The Covid epidemic is here to stay," Rousseau added. "We think that the incidence has increased by around 30% since last week," even if these figures should be taken "with great caution," for since July 1, the virus' surveillance systems have been considerably streamlined.

But it is not so much the resurgence of the epidemic since mid-summer that is worrying experts. To date, the number of new infections remains limited. In addition, "there is currently no massive increase in hospitalizations," said the COVARS.

The emergence of new SARS-CoV-2 sub-variants that can escape immune defenses – defenses painstakingly acquired over almost three years of vaccine injections and infections – is more of concern. "This ability to escape bothers us most," said Autran. "The immune response we have built up, particularly against the BA.4 and BA.5 variants over the past year, does not protect us well against the variants currently circulating."

Most people hospitalized or in intensive care for Covid-19 today show feeble immune responses to these current variants. Unsurprisingly, most are frail patients, either elderly or suffering from chronic pathologies, "which reinforces the need for appropriate protective measures for these populations," the COVARS said.

In the face of these weakened immune defenses, a new weapon has arrived at just the right time: New vaccines specifically developed against the XBB.1.5 strain. Vaccines used until now have primarily targeted the historical strain of the virus (the Wuhan strain), or the historical strain coupled with the BA.1 variant (from the Omicron lineage), or the BA.4-5 strains (also derived from Omicron).

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