Key Points

• The spread of acute respiratory infections in Normandy was characterized by two epidemic waves: a first wave of moderate intensity in September–October, followed by a second, more intense wave at the end of the year linked to the co-circulation of RSV and influenza.
• An increase in COVID-19 activity was observed between September and October 2025, at a moderate level. This marks the second consecutive season in which an increase in COVID-19 activity has been observed during this period.
• The bronchiolitis epidemic followed the same pattern as the previous year, with low intensity, particularly in emergency departments. This situation may reflect the positive impact of the preventive measures introduced in 2023, particularly the immunization of infants and the vaccination of pregnant women, which helped reduce severe cases among young children.
• The influenza epidemic lasted 11 weeks and was characterized by the co-circulation of the AH1N1 and AH3N2 viruses. Morbidity indicators reached high levels, and significant mortality was observed, at levels comparable to the epidemics of 2022–2023 and 2024–2025.
• Despite a slight increase in influenza vaccination coverage, it remains below national targets, particularly among healthcare workers.