Key points

Acute respiratory infections

• Early and sustained activity of lower respiratory tract infections (LRTI) beginning in November 2024, with high activity observed in January, primarily linked to the flu epidemic.

Influenza

• Intense and prolonged circulation of the virus, from early December (W49-2024) to late February (W09-2025), representing 13 weeks of the epidemic compared to an average of 10 weeks over the 2014–2024 period, with very high activity in both primary care and emergency departments.

• More than 32,000 SOS Médecins calls for influenza/flu-like illness during the epidemic phase, representing a 110% increase compared to the previous season’s epidemic.

• Nearly 16,200 emergency department visits for influenza were recorded during the epidemic according to the OSCOUR® network, 2.5 times more than the previous season. Of these, 3,142 led to hospitalization (19.4%), a volume 2.8 times higher than that observed in 2023–2024.

• Unusual and sustained co-circulation of the three influenza viruses: A(H1N1), A(H3N2), and B/Victoria.

Bronchiolitis

• The epidemic lasted 9 weeks, from mid-November (W46-2024) to mid-January (W02-2025), with a peak in activity in late November–early December (W48–W49-2024).

• Activity in private practice was lower than in previous seasons, with low intensity: 639 cases of bronchiolitis recorded by SOS Médecins, representing a 36% decrease compared to 2023–2024.

• In emergency departments, 2,942 visits were recorded among children under 2 years of age, including 910 hospitalizations (31%), also marking a significant decrease compared to previous seasons.

Acute gastroenteritis

• Activity increased later than in previous seasons, beginning in late February (W9) and peaking in early to mid-April (W14–W15).

• Activity indicators remained at levels comparable to those of previous seasons.

COVID-19

• Activity remained at very low levels during the 2024–2025 winter season.