France’s most recent winter respiratory season saw a notable rise in vaccination rates, yet the actual protection offered against the flu remained modest. According to a final report from Santé publique France (SPF), the real-world effectiveness of the influenza vaccine for the 2025-2026 season was estimated at 30% across all age groups.
This “moderate” level of efficacy comes despite a concerted public health push that saw vaccination coverage reach its highest levels since the COVID-19 pandemic. The epidemic, which spanned 10 weeks from December 2025 to mid-February 2026, was driven exclusively by type A viruses, challenging the healthcare system’s capacity and testing the precision of the seasonal vaccine strain.
While the overall effectiveness may seem low, health officials note that the vaccine performed better than expected given the genetic drift of the virus. Specifically, a significant antigenic divergence in the “sub-clade K” of the A(H3N2) virus made it more elusive, yet the vaccine still provided a critical layer of defense, particularly for the youngest patients.
Vaccination Trends and Demographic Disparities
The 2025-2026 campaign, which ran from mid-October through February, succeeded in increasing the number of protected individuals among high-risk populations. Overall coverage for those targeted for vaccination reached nearly 50%, a rise of 3.1 percentage points over the previous year. This trend was mirrored across different age brackets, reflecting a renewed public commitment to preventative care.
However, the actual protection conferred by the shot varied wildly depending on the age of the recipient. While the general average sat at 30%, the vaccine was significantly more potent in children and adolescents. For those aged 0-17, effectiveness reached 67%, providing a robust shield against symptomatic illness. In contrast, the efficacy dropped to 34% for adults aged 18-64 and fell further to 23% for those 65 and older.
| Age Group | Estimated Effectiveness |
|---|---|
| 0–17 years | 67% |
| 18–64 years | 34% |
| 65+ years | 23% |
| All Ages (Average) | 30% |
These figures, produced by the National Reference Center (CNR) using data from the Relab network of city laboratories, highlight a recurring challenge in geriatric medicine: the phenomenon of immunosenescence, where the aging immune system produces a weaker response to vaccination.
The Strain on Hospital Infrastructure
The impact of the 2025-2026 flu season was felt unevenly across the French medical landscape. In primary care, the intensity was described as “low to moderate.” There were approximately 1.2 million consultations attributed to the flu via the Sentinelle network, supplemented by nearly 158,000 interventions by SOS Médecins for flu-like syndromes. These numbers represent a marked decrease compared to the 2024-2025 season.
The situation was more precarious within the hospital system. The pressure on emergency departments peaked during the final week of 2025, while hospitalizations reached their zenith in the first week of January 2026. Throughout the winter, approximately 115,000 emergency room visits and 24,000 subsequent hospitalizations were recorded for influenza or flu-like syndromes.
Of particular concern to clinicians is the increasing severity of cases requiring hospital care. SPF reported that 21% of emergency room visits for flu-like symptoms resulted in hospitalization during the 2025-2026 season. This is an increase from 19% the previous year and significantly higher than the 16% average recorded between 2016 and 2025. This suggests that while fewer people may have been severely ill those who did enter the hospital were more likely to require admission.
Mortality and Excess Death Tolls
The human cost of the season remained significant. At the peak of the epidemic in the second week of January, influenza was listed as the cause of death in 7.3% of all deaths reported via electronic certificates. In total, 4,389 deaths were specifically attributed to the flu through this reporting system, a decrease from the 4,925 deaths seen in the prior season.
When looking at “excess mortality”—the number of deaths above what is normally expected for that time of year—the 2025-2026 season was less lethal than the one preceding it. SPF estimates there were 12,700 excess deaths during the epidemic period, compared to 17,900 in the 2024-2025 season.
The divergence between the moderate effectiveness of the vaccine and the overall reduction in deaths is partly attributed to the lower overall intensity of the epidemic in the community. However, the “moderate” 30% effectiveness is still viewed by public health experts as a success given the “strong antigenic divergence” of the circulating sub-clade K virus, which often renders vaccines less effective.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Please consult a healthcare provider for vaccination guidance and health concerns.
Public health authorities will continue to monitor circulating strains as they prepare for the next seasonal cycle. The next major checkpoint will be the World Health Organization’s (WHO) recommendations for the 2026-2027 vaccine composition, which will aim to better match the evolving genetic profile of type A viruses.
We invite our readers to share their experiences with this season’s respiratory health challenges in the comments below.
