Early estimates of 2016/17 seasonal influenza vaccine effectiveness in primary care in France

Cécile Souty (1) , Ana-Maria Vilcu (1) , Lisandru Capai (1, 2) , Sylvie van Der Werf (3, 4) , Martine Valette (5) , Thierry Blanchon (1) , Bruno Lina (5, 6) , Sylvie Behillil (3, 4) , Thomas Hanslik (1, 7, 8) , Alessandra Falchi (2)

1 iPLESP - Institut Pierre Louis d'Epidémiologie et de Santé Publique
2 EA Bioscope Corse Méditerranée : Dynamique des infections virales en milieu insulaire
3 GMV-ARN (UMR_3569 / U-Pasteur_2) - Génétique Moléculaire des Virus à ARN - Molecular Genetics of RNA Viruses
4 CNR - Centre National de Référence des virus influenzae (Grippe)
5 Virpath - Virpath-Grippe, de l'émergence au contrôle -- Virpath-Influenza, from emergence to control
6 CNR des virus influenza - Laboratoire de Virologie [GH Nord HCL, Lyon]
7 Service de Médecine Interne
8 UVSQ Santé - Université de Versailles Saint-Quentin-en-Yvelines - UFR Sciences de la santé Simone Veil

Background: The ongoing 2016/17 influenza epidemic in France is characterized by the circulation of A(H3N2) viruses, known to cause more severe illness among at risk populations.Objectives: The purpose of our study was to provide early influenza vaccine effectiveness (IVE) estimates for the ongoing influenza epidemic in France and compare these estimates over the six post-pandemic IVE.Study design: We used clinical and virological data collected in primary care by the French Sentinelles network. IVE in preventing influenza infection was estimated by the test-negative design method. The screening method was used to estimate IVE in preventing medically-attended influenza-like illness among target groups (<65 year with chronic diseases and ≥65 years) since 2010/11 influenza epidemic.Results: Early IVE estimates in primary care against influenza A(H3N2) were 48% (95% confidence interval (CI): 22 to 66) overall and 39% (95% CI: -17 to 69) among elderly (aged 65 and older). In comparison to the last six epidemics, 2016/17 early IVE in preventing influenza-like illness among target groups showed VE estimates higher to those reported during the 2011/12 and 2014/15 epidemics.Conclusions: The moderate 2016/17 IVE estimates were higher than those estimated during influenza A(H3N2) epidemics with vaccine mismatch.

Mots clés: influenza; influenza-like illness; primary care; vaccine effectiveness

Domaines: Sciences du Vivant [q-bio]

Cécile Souty, Ana-Maria Vilcu, Lisandru Capai, Sylvie van Der Werf, Martine Valette, et al.. Early estimates of 2016/17 seasonal influenza vaccine effectiveness in primary care in France. Journal of Clinical Virology, 2017, 95, pp.1 - 4. ⟨10.1016/j.jcv.2017.08.002⟩. ⟨hal-01582085⟩