Influenza vaccine effectiveness against detected infection in the community, France, October 2024 to February 2025

Abstract

Influenza circulates at high levels in Europe since November 2024. Using a test-negative study based on data from French community laboratories between October 2024 and February 2025, we estimated vaccine effectiveness (VE) against PCR-detected influenza infection (44,420/15,052; positive/negative individuals). For all age groups, the overall VE was 42% (95%CI:37–46%), with 26% (95%CI:18–34%) against influenza A and 75% (95%CI:66–82%) against influenza B. Among individuals ≥65-year-olds VE was 22% (95%CI:13–30%) and among 0–64-year-olds, 60% (95%CI:56–65%). The incidence of influenza has steeply risen in France and in Europe since November 2024, with, at the end of 2024, a high PCR-test positivity rate for influenza virus and elevated numbers of primary care consultations, as well as increased hospital and intensive care unit (ICU) admissions due to this illness [1-5]. In the United Kingdom (UK), influenza hospital and ICU admissions were in early January 2025 twice as frequent as in the peak of the 2023/24 season for this disease [4]. This interim report provides an overview of vaccine effectiveness (VE) estimates in France based on data from community laboratories. The VE overall and by virus type is presented, as well as among older adults, a high-priority group for vaccination.