Key points

Acute respiratory infections (ARI)

• Season characterised by two successive peaks: in late December, linked to the bronchiolitis epidemic and COVID-19, and in late January, due to the influenza epidemic

• Impact on healthcare provision in general practice and hospitals lower than for the 2022–2023 season

Influenza

• Epidemic of expected duration lasting from late December to late February, in total 10 weeks

• Moderate scale and intensity in general practice:

  • 1.5 million consultations for influenza-like illness (Sentinelles network)

  • Influenza-like illness accounted for 18% of SOS Médecins consultations at the peak of the epidemic in late January (W05-2024)

• Moderate severity, with 14,000 hospitalisations after a visit to the emergency department

• Circulation of A(H1N1)pdm09 viruses dominated

• Vaccination coverage estimated at 47.1% among at-risk individuals targeted for vaccination, and 54.0% among people aged 65 and over, lower than in 2022–2023

Bronchiolitis

• Epidemic came early in mainland France, starting in mid-October (W42-2023), 4 weeks earlier than usual, and ending in early January (W01-2024)

• Epidemic of expected duration, in total 12 weeks

• Proportion of hospitalisations for bronchiolitis out of all hospitalisations after a visit to the emergency department in children under 2: 44.3% at the peak of the epidemic in late November (W48-2023)

• Intensity comparable to that of epidemics prior to the emergence of COVID-19. Lower intensity than last season (2022–2023 season), which was particularly high

• An immunisation campaign using the monoclonal antibody nirsevimab (Beyfortus®), a preventive treatment for RSV infections in infants, was organised from mid-September 2023

COVID-19

• Dynamics and intensity of epidemic waves comparable to those of 2022–2023

• Increase in indicators from July 2023 with two peaks, in September and December. Decline since mid-December, indicators at low levels since mid-February

• Greatest proportion of hospitalisations in December (3.3% in W50-2023)

• Circulation dominated by JN.1 variant since late November 2023

• Vaccination coverage estimated at 30.2% among people aged 65 and over by the end of the vaccination campaign from October 2023 to February 2024