1914. Trivalent Inactivated Influenza Vaccine Effectiveness against Hospitalized Influenza in France During 2014-2015 Winter : Results from the FLUVAC Study
Session: Poster Abstract Session: Vaccines: Influenza
Saturday, October 10, 2015
Room: Poster Hall
  • Poster Odile Launay_ID Week FLUVAC 01.10 2015-VF.pdf (98.1 kB)
  • Background:

    Elderly and people of any age with underlying chronic conditions are among those targeted by seasonal influenza vaccination in France, as they are the most susceptible group to severe influenza outcome. An update of seasonal influenza vaccines is needed yearly, sine influenza viruses constantly evolve. For this reason, there is a need for vaccine effectiveness (VE) studies among target population to assess the vaccination strategies. During the 2014-15 influenza season, mainly A(H3N2) viruses circulated and antigenic drift was observed in a high proportion of A(H3N2) viruses.


    Hospitalised patients (> 18 years) reporting an influenza-like illness within the seven days before admission were prospectively enrolled and swabbed in 6 hospitals in France. Influenza vaccination dates were confirmed by medical record. The influenza vaccine effectiveness (IVE) was estimated as [100% × (1 - adjusted odds ratio)] for vaccination in cases (RT-PCR positive for influenza) versus test-negative controls, adjusted on age, sex, chronic disease and exposure to children.


    Influenza was detected in 286 of 597 patients (48%); 147 (51%) had influenza A(H3N2); 73 (26%) influenza A(H1N1)pdm09, 14 (5%) influenza A unsubtyped and 54 (19%) B influenza. Two patients had no available vaccination date. Overall, adjusted IVE was 5% (95CI:-35%;33%, N=595) against all influenza viruses. Adjusted IVE against A(H3N2) was -6% (95%CI:-62%;31%; N=455), -55% (95%CI:-245%;30% N=159) among patients <65 years and 8% (95%CI:-52%;44%; N=296) among patients aged ≥65 years. Adjusted IVE was 5% (95%CI: -72%;47%; N=381) against A(H1N1)pdm09, 7% (95%CI:-131%;73%; N=155) among patients <65 years and 37% (95%CI:-41%;72%; N=226)) among those aged ≥65 years.


    The results suggest that the 2014-15 vaccine was ineffective to prevent hospitalized influenza. The low IVE may be explained by an imperfect match between vaccine and circulating strains in France. Reaching a larger sample size would allow for measuring IVE with more precision.

    Odile Launay, MD, PhD1,2, Nezha Samih-Lenzi, PhD2, Florence Galtier, MD2,3, Philippe Vanhems, MD, PhD2,4, Pierre Loulergue, MD1, Stephane Jouneau, MD, PhD2,5, Xavier Duval, MD, PhD2,6, Déborah Postil, MD2,7, Zineb Benderra-Lesieur, PhD2, Martine Valette, PhD8, Bruno Lina, MD, PhD9 and Fabrice Carrat, MD, PhD10, (1)CIC De Vaccinologie Cochin-Pasteur, Aphp, Université Paris Descartes, Sorbonne Paris Cité, Paris, France, (2)Inserm, F-CRIN, Innovative clinical research network in vaccinology (I-REIVAC), Paris, France, (3)CIC de Montpellier , Hôpital Saint-Eloi, CHU de Montpellier, Montpellier, France, (4)Service D'hygiène, épidémiologie Et Prévention, Groupement Hospitalier Edouard Herriot, Lyon, France, (5)Service De Pneumologie, Hôpital Pontchaillou, CHU de Rennes, Rennes, France, (6)CIC de Bichat, Hôpital Bichat-Claude Bernard, APHP, Paris, France, (7)CIC de Limoges, CHU Dupuytren, Limoges, Limoges, France, (8)CNR Virus Influenza, Hospices Civils de Lyon, Bron, France, (9)Cnr Virus Influenza Hcl, University of Lyon, Lyon, France, (10)U707, Inserm, Université Pierre et Marie Curie, Paris, France


    O. Launay, None

    N. Samih-Lenzi, None

    F. Galtier, None

    P. Vanhems, None

    P. Loulergue, None

    S. Jouneau, None

    X. Duval, None

    D. Postil, None

    Z. Benderra-Lesieur, None

    M. Valette, None

    B. Lina, None

    F. Carrat, None

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