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
Creators: name: Valenciano, Marta
name: Kissling, Esther
name: Reuss, Annicka
name: Rizzo, C.
name: Gherasim, A.
name: Horváth, Judit K.
name: Domegan, L.
name: Pitigoi, Daniela
name: Machado, Ausenda
name: Bella, A.
name: Paradowska-Stankiewicz, I.
name: Larrauri, A.
name: Ferenczi, A.
name: O´Donell, Joan
name: Lazar, M.
name: Pechirra, P.
name: Korczyńska, M. R.
name: Pozo, Francisco
name: Moren, A.
Publisher: name: Robert Koch-Institut, Infektionsepidemiologie
Year: 2016
Subjects: subject: Humans
subject: Female
subject: Male
subject: Adolescent
subject: Adult
subject: Aged
subject: Middle Aged
subject: Young Adult
subject: Europe/epidemiology
subject: Population Surveillance
subject: Seasons
subject: Influenza Vaccines/administration &amp; dosage
subject: Influenza Human/prevention &amp; control
subject: Vaccination/statistics &amp; numerical data
subject: Child Preschool
subject: Infant
subject: Child
subject: Sensitivity and Specificity
subject: Influenza Human/virology
subject: Influenza Human/epidemiology
subject: Infant Newborn
subject: Case-Control Studies
subject: European Union
subject: Influenza A Virus H1N1 Subtype/immunology
subject: Influenza A Virus H1N1 Subtype/isolation &amp; purification
subject: Influenza A Virus H3N2 Subtype/immunology
subject: Influenza A Virus H3N2 Subtype/isolation &amp; purification
subject: Influenza B virus/immunology
subject: Influenza B virus/isolation &amp; purification
subject: Influenza Vaccines/immunology
subject: Outcome Assessment (Health Care)
subject: Laboratories
subject: Vaccine Potency
subject: Primary Health Care
subject: 610 Medizin

description: 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.