The 2026-2027 bronchiolitis season in France is covered by a prevention campaign that began on 14 September 2026 in mainland France and is due to run until 28 February 2027. Santé publique France, the French public health agency, expects the epidemic to start around mid-November and end around mid-January. As of 14 October, all bronchiolitis indicators were still at baseline level in every region.
This article brings together what the official documents published since the end of the summer say: the Santé publique France note on the campaign timetable, the arrangements set out by the Direction générale de la santé (DGS, the French health ministry's directorate-general), and the first weekly bulletin of the season. The general recommendations, everyday precautions and the opinion of the Haute Autorité de santé (HAS) on nirsevimab are covered in detail in our article on the bronchiolitis prevention campaign and RSV. We won’t repeat them here.
Bronchiolitis 2026-2027: what are the campaign dates?
According to the arrangements set out by the Direction générale de la santé in a DGS-Urgent message dated 10 August 2026, and reported by Vidal on 2 September, the campaign covers the following periods:
- Mainland France: from 14 September 2026 to 28 February 2027;
- Martinique, Guadeloupe, Saint-Martin and Saint-Barthélemy: from 31 August 2026 to 28 February 2027;
- Réunion: from 28 September 2026 to 28 March 2027;
- Mayotte: from 1 October 2026 to 31 May 2027;
- French Guiana: all year round, as the virus circulates continuously there.
The end dates are indicative. They may be brought forward or pushed back depending on how the epidemic actually develops. In 2025, the campaign started on 1 September in mainland France. This year’s start has therefore been moved back by two weeks, to match the timetable estimated by Santé publique France.
Why does the campaign start in mid-September?
Asked by the Direction générale de la santé in May 2026, Santé publique France published a decision-support note on 4 September. It draws on the share of bronchiolitis in emergency department visits and the hospital admissions that follow, via the OSCOUR network, and on the RSV positivity rate in respiratory samples.
For mainland France, the agency places the at-risk period between week 38 of 2026, in other words mid-September, and week 9 of 2027, in other words early March. It recommends that maternal vaccination and immunisation of newborns be offered throughout this period. The timetable is designed so that babies under two months old are protected from the very start of the at-risk period. Protection from an antibody injection or from vaccination during pregnancy is estimated to last at least five months.
What previous seasons have taught us
Before the Covid-19 pandemic, the bronchiolitis epidemic began in mid-November (median date), peaked in December and ended in late January. The 2021-2022 and 2022-2023 seasons came six weeks earlier. The 2024-2025 and 2025-2026 seasons returned to a timetable close to the pre-Covid one: starting in week 47 and ending in week 2, so eight weeks of epidemic, a shorter duration than usual.
On this basis, Santé publique France estimates that the virus could begin circulating in week 41, in other words early October. The epidemic would start around week 47, around 16 November, and end around week 2 of 2027, with circulation possible until March. The agency itself stresses that this prediction has remained difficult since the pandemic.
Where does the epidemic stand in mid-October?
The national acute respiratory infections bulletin published on 14 October 2026 covers week 41, from 5 to 11 October. It shows that bronchiolitis indicators were at baseline level in all regions. Activity was even lower than at the same time last year, both in GP practices and in hospitals.
The RSV positivity rate in samples also remained at baseline level. However, other viruses that can cause bronchiolitis were actively circulating in mainland France, particularly rhinoviruses and enteroviruses. So a baby can develop bronchiolitis in October even though the RSV epidemic hasn’t started. Our guidance on fever in babies and when to see a doctor still applies in this case.
What prevention options are there for a baby born this autumn?
Two strategies exist side by side, and the Haute Autorité de santé considers them alternatives. Parents choose one or the other.
Vaccination during pregnancy
The Abrysvo vaccine is given as a single dose between weeks 32 and 36 of pregnancy, counted from the last period. It protects the baby from birth for several months. In France, it is fully covered (100%) under maternity insurance. In 2025-2026, 53% of eligible pregnant women had it, a figure we look at in detail in our article on vaccination during pregnancy.
Antibodies for the newborn
Nirsevimab, sold under the name Beyfortus, is still available: a 50 mg dose if your baby weighs less than 5 kg, 100 mg above that. New this season is clesrovimab, brand name Enflonsia, as a single 105 mg dose whatever the baby’s weight. Both products are intended for all babies in their first season. From a high-street pharmacy, they are reimbursed at 65% by the Assurance Maladie, the French national health insurance. At the maternity unit, they are funded as part of the hospital stay.
Palivizumab, Synagis, remains reserved for premature or high-risk babies, with monthly injections during the epidemic period. A baby born less than fourteen days after their mother’s vaccination, or born prematurely, should receive an antibody injection despite the vaccination. Families affected by a premature birth will find guidance in our article on premature birth in France.
And for a second season?
Children under 24 months who remain vulnerable because of recent bronchopulmonary dysplasia or congenital heart disease can receive nirsevimab at 200 mg for their second season. This is something to discuss with the paediatrician who follows your child.
What does this timetable mean for parents?
A baby born in October or November arrives at the most exposed time. If the mother wasn’t vaccinated during pregnancy, the antibody injection is usually given at the maternity unit before going home. It can also be given later at the doctor’s or at a pharmacy, on prescription. It isn’t too late in December: the campaign runs until the end of February, and protection lasts at least five months.
A baby born in the spring who has already been through one winter is generally no longer concerned, except in particular medical situations. For them, prevention relies on everyday precautions: handwashing, no contact with people who have a cold, no smoking in the home, airing rooms. These precautions also apply to siblings and to nursery, where viruses spread quickly, as our article on babies falling ill at nursery explains.
Bronchiolitis isn’t the only respiratory infection of the winter. The flu vaccination campaign began on 13 October and concerns pregnant women and those around babies. Our article on flu in babies and the 2026-2027 campaign gives the details. The full infant vaccination schedule is in our article on baby vaccinations in France.
What we’ll be following over the coming weeks
Every Wednesday, Santé publique France publishes a national acute respiratory infections bulletin, with an alert level for each region. It flags when a region moves into the pre-epidemic and then the epidemic phase. The agency has also announced an estimate of nirsevimab coverage before the end of 2026. We’ll update this article when these figures are published.
A season’s epidemic figures can only be read in hindsight. The record of the 2024-2025 and 2025-2026 seasons, eight weeks each, is at this stage the best indication of what awaits families this winter, with the caveat that the agency itself expresses.
Sources
- Santé publique France, “Note d'aide à la décision. Date de début de la prochaine campagne d'immunisation des nouveau-nés contre la bronchiolite à VRS pour la saison 2026-2027 (France hexagonale et DROM)”, published on 4 September 2026.
- Santé publique France, “Bulletin Infections respiratoires aiguës (grippe, bronchiolite, COVID-19). Semaine 41. Édition nationale”, published on 14 October 2026.
- Direction générale de la santé, DGS-Urgent no. 2026-10 of 10 August 2026, arrangements for the 2026-2027 prevention campaign, as detailed by Vidal, “Bronchiolite du nourrisson : la DGS détaille les modalités de la campagne de prévention 2026-2027”, 2 September 2026.
- Santé publique France, “Bronchiolite” page, updated on 15 April 2026.
