title: Vaccine effectiveness in preventing laboratory-confirmed influenza in primary care patients in a season of co-circulation of influenza A(H1N1)pdm09, B and drifted A(H3N2), I-MOVE Multicentre Case-Control Study, Europe 2014/15.
abstract: Influenza A(H3N2), A(H1N1)pdm09 and B viruses co-circulated in Europe in 2014/15. We undertook a multicentre case-control study in eight European countries to measure 2014/15 influenza vaccine effectiveness (VE) against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. General practitioners swabbed all or a systematic sample of ILI patients. We compared the odds of vaccination of ILI influenza positive patients to negative patients. We calculated adjusted VE by influenza type/subtype, and age group. Among 6,579 ILI patients included, 1,828 were A(H3N2), 539 A(H1N1)pdm09 and 1,038 B. VE against A(H3N2) was 14.4% (95% confidence interval (CI): -6.3 to 31.0) overall, 20.7% (95%CI: -22.3 to 48.5), 10.9% (95%CI -30.8 to 39.3) and 15.8% (95% CI: -20.2 to 41.0) among those aged 0-14, 15-59 and  ≥60  years, respectively. VE against A(H1N1)pdm09 was 54.2% (95%CI: 31.2 to 69.6) overall, 73.1% (95%CI: 39.6 to 88.1), 59.7% (95%CI: 10.9 to 81.8), and 22.4% (95%CI: -44.4 to 58.4) among those aged 0-14, 15-59 and  ≥60 years respectively. VE against B was 48.0% (95%CI: 28.9 to 61.9) overall, 62.1% (95%CI: 14.9 to 83.1), 41.4% (95%CI: 6.2 to 63.4) and 50.4% (95%CI: 14.6 to 71.2) among those aged 0-14, 15-59 and ≥60 years respectively. VE against A(H1N1)pdm09 and B was moderate. The low VE against A(H3N2) is consistent with the reported mismatch between circulating and vaccine strains.
authors.affiliation: Epidemiology Department, EpiConcept, Paris, France.
authors.forename: Marta
authors.initials: M
authors.lastname: Valenciano
authors.forename: Esther
authors.initials: E
authors.lastname: Kissling
authors.forename: Annicka
authors.initials: A
authors.lastname: Reuss
authors.forename: Caterina
authors.initials: C
authors.lastname: Rizzo
authors.forename: Alin
authors.initials: A
authors.lastname: Gherasim
authors.forename: Judit Krisztina
authors.initials: JK
authors.lastname: Horváth
authors.forename: Lisa
authors.initials: L
authors.lastname: Domegan
authors.forename: Daniela
authors.initials: D
authors.lastname: Pitigoi
authors.forename: Ausenda
authors.initials: A
authors.lastname: Machado
authors.forename: Iwona Anna
authors.initials: IA
authors.lastname: Paradowska-Stankiewicz
authors.forename: Antonino
authors.initials: A
authors.lastname: Bella
authors.forename: Amparo
authors.initials: A
authors.lastname: Larrauri
authors.forename: Annamária
authors.initials: A
authors.lastname: Ferenczi
authors.forename: Mihaela
authors.initials: M
authors.lastname: Lazar
authors.forename: Pedro
authors.initials: P
authors.lastname: Pechirra
authors.forename: Monika Roberta
authors.initials: MR
authors.lastname: Korczyńska
authors.forename: Francisco
authors.initials: F
authors.lastname: Pozo
authors.forename: Alain
authors.initials: A
authors.lastname: Moren
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005060:Europe / Q000453:epidemiology; D005062:European Union; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology* / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology* / Q000302:isolation & purification; D009981:Influenza B virus / Q000276:immunology* / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D007753:Laboratories; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011159:Population Surveillance; D011320:Primary Health Care; D012621:Seasons; D012680:Sensitivity and Specificity; D014611:Vaccination / Q000706:statistics & numerical data; D064166:Vaccine Potency; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines
keywords: influenza; influenza vaccine effectiveness; multicentre case-control study; vaccines and immunisation