Acute bronchiolitis is a respiratory illness that primarily affects infants under 2 years of age. It is highly contagious and is most commonly caused by the respiratory syncytial virus (RSV), although other viruses can also be responsible. Currently, two strategies for preventing RSV infections in infants are available in France: passive immunization of the newborn through the administration of monoclonal antibodies and vaccination of the mother during pregnancy. The French National Authority for Health recommends that vaccination and immunization campaigns be conducted concurrently and that they begin either prior to or at the start of the epidemic period and continue until the end of that period. On May 26, 2025, the Directorate General of Health requested the support of Santé publique France to obtain an opinion on the start date of the next immunization campaign for newborns against RSV bronchiolitis for the 2025–2026 season in mainland France as well as in each of the overseas departments and regions (DROM). The response¹ to this request was issued on June 17, 2025, and proposes two strategies for French Guiana: 1) immunization campaigns for newborns and maternal vaccination from July 28, 2025, until the end of the epidemic, or 2) start of the maternal vaccination campaign on June 2, 2025, and start of the newborn immunization campaign on July 28, 2025, until the end of the epidemic. The French Guiana Regional Health Agency is regularly contacted by pediatricians in maternity wards who report hospitalizations of infants for bronchiolitis throughout the year, not just during epidemic periods. It is therefore exploring the possibility of preventing these cases outside of epidemic periods through vaccination during pregnancy and/or immunization of newborns against RSV over a longer period. Thus, on July 17, 2025, the French Guiana Regional Health Agency submitted a request to Santé publique France to assess the RSV situation among infants under 2 years of age in the region, with a view to potentially revising the regional strategy for newborn immunization and vaccination of pregnant women (request no. 25A-00119 of July 17, 2025). This decision-making guidance note is in response to that referral.

Learn more:

• Santé publique France’s expert review procedure

• the expert assessment by Santé publique France