Key Points

Acute Respiratory Infections - Summary of the 2024-2025 Winter Season

• Influenza and influenza-like illnesses:

  • A 12-week epidemic lasting from early December (Week 50, 2024) to late February (Week 9, 2025)

  • Very high intensity in community practice and hospitals

  • Significant impact of the epidemic in terms of mortality

  • Unusual co-circulation of the three viruses A(H1N1)pdm09, A(H3N2), and B/Victoria

  • Vaccination coverage estimated at 50% among those aged 65 and older, and 21% among at-risk individuals under 65, relatively stable compared to that of 2023–2024.

• Bronchiolitis:

  • Short-lived epidemic (8 weeks) from mid-November (W47-2024) to mid-January (W02-2025)

  • Low-intensity outbreak

• COVID-19:

  • Low levels of viral circulation and syndromic activity throughout the 2024-25 winter season

Pertussis

• Despite an increase in the positivity rate of PCR tests for pertussis in March, pertussis-related activity in emergency departments and at SOS Médecins clinics remains low in the Provence-Alpes-Côte d'Azur region.