Bulletin N°13 – December 2025

1) On the side of the authorities.

In the PLFSS voted a few days ago, it is confirmed that vaccination against meningococci B and ACYW is now compulsory for all children born from January 1, 2023. Clearly, this obligation also concerns children who are now between 2 and 3 years. Another surprise of the PLFSS is the vote on an article (Art. L. 4211-4.) allowing certain vaccines to be available in health centers and among doctors and nurses. We are not there yet and we will wait for the decrees to believe it. Furthermore, vaccination of women and men against human papillomavirus (HPV) up to the age of 26 ans East finally officially refunded.

2) On the epidemic side: data from the PARI pediatric surveillance network (ACTIV-AFPA) and the VIGIL observatory (ACTIV-AFPA).

The bronchiolitis epidemic, who is in rapid decline (Lien 1), was the most modest for 9 years among children followed by pediatricians. The vast majority of children were sampled using multiplex AAZ antigen tests (VRS, grippe A & B, COVID). Le VRS was involved in more than 60% of cases. This favorable situation can be explained both by a excellent maternity immunization coverage (maternal vaccination or monoclonal antibodies), close to 90% in children born since September 1, and also by a Nirsevimab catch-up satisfactory by pediatriciansestimated at approximately 80% for 3-6 months, which is far from being the case for other vaccinators. PARI data also shows a increase in median age children with bronchiolitis: 7.5 months before Nirsevimab has 11 months currently.

If we compare this epidemic to those of previous years, the particularity of this season is the fairly strong concomitance with the flu epidemic. However, unlike the flu, there is little probability that the bronchiolitis epidemic will start again following school holidays (Lien 2).

The flu epidemic, for its part, began with a unusual precocity et has not yet reached its peak. Rapid diagnostic tests have been widely used (in more than 80% of flu-like illnesses) et more than 80% of these tests were positive for influenza A (Lien 3). It is predictable that, as in previous years, the epidemic starts again and grows after the end of year holidays (Christmas and New Year’s Day).
The subclade K (also called J.2.4.1) corresponds to a flu virus A(H3N2)known to be more virulent than A(H1N1) viruses. It is responsible for this epidemic phase, having accumulated several mutations leading to hemagglutinin changes. It is probably more transmissiblefew people have natural immunity to this clade, and the latest field efficacy data from England suggests a modest effectiveness of injectable vaccineof the order of 30 to 40 %, while she is more than double for the nasal vaccine. Once again, we welcome the lack of foresight of the so-called “transparency” Commission; But we end up getting used to it…

Data from the VIGIL observatory show that, compared to PCR, the antigen test used this year in children presents, in addition to specificity already known as excellent (close to 100%)a sensitivity also excellent (≈ 90%)both for the VRS that for the circulating flu strain.

3) For your information

We advise you to read the Public Health Barometer France (Lien 4)presenting the results of the 2024 edition on vaccination: status of membership etdescription of reluctance. It appears, however, that the Vaccine confidence is lowest in disadvantaged populationswith a deviation of approximately –10% compared to advantaged populationsemphasizing the need toreinforced education and support efforts.

4) On the product side

The Capvaxive®pneumococcal conjugate vaccine intended for people over 65 years old and to adults at risk for pneumococcal infectionsis now available in pharmacies and reimbursed. He is recommended by CTV for these patients, at the same level as Prevenar 20®.

Infovac invites you to participate in his investigation concerning pneumococcal vaccination in adults.

5) In response to your questions

Should I vaccinate against chickenpox a 74-year-old patient who I was supposed to vaccinate against shingles, but who has no memory of having had chickenpox and whose varicella serology is negative?

Non !! In the elderly, negative VZV serology does not exclude a previous infection, which may reflect a drop in antibodies linked to immunosenescence. Given the very high prevalence of chickenpox, the hypothesis of a total absence of contact with VZV is unlikely, even without a known clinical history.

There is no recommendation to document VZV serology before administering the shingles vaccine (Shingrix®). Regarding a inactivated recombinant vaccineits administration is without risk, including in a subject potentially not immunized against chickenpox. In addition, including in immunocompromised, seronegative subjects and without a history of chickenpox, Shingrix® is immunogenic and effective.

On the other hand, it is less certain that this vaccine also protects against varicellaet there is nothing to confirm that vaccination against chickenpox at the age of 74 is without risk in this type of patient.

Robert Cohen, Isabelle Hau, Franck Thollot, Carterine Weil-Olivier, Didier Pinquier, Francois Vie le Sage, Pierre Bakache, Piedre Bégué, Georges Thiebault, Véronique Dufour, Anne-Sophie Romain, Marie-Aliette Dommergues, Hervé Haas