title: I-MOVE multicentre case-control study 2010/11 to 2014/15: Is there within-season waning of influenza type/subtype vaccine effectiveness with increasing time since vaccination?
abstract: Since the 2008/9 influenza season, the I-MOVE multicentre case-control study measures influenza vaccine effectiveness (VE) against medically-attended influenza-like-illness (ILI) laboratory confirmed as influenza. In 2011/12, European studies reported a decline in VE against influenza A(H3N2) within the season. Using combined I-MOVE data from 2010/11 to 2014/15 we studied the effects of time since vaccination on influenza type/subtype-specific VE. We modelled influenza type/subtype-specific VE by time since vaccination using a restricted cubic spline, controlling for potential confounders (age, sex, time of onset, chronic conditions). Over 10,000 ILI cases were included in each analysis of influenza A(H3N2), A(H1N1)pdm09 and B; with 4,759, 3,152 and 3,617 influenza positive cases respectively. VE against influenza A(H3N2) reached 50.6% (95% CI: 30.0-65.1) 38 days after vaccination, declined to 0% (95% CI: -18.1-15.2) from 111 days onwards. At day 54 VE against influenza A(H1N1)pdm09 reached 55.3% (95% CI: 37.9-67.9) and remained between this value and 50.3% (95% CI: 34.8-62.1) until season end. VE against influenza B declined from 70.7% (95% CI: 51.3-82.4) 44 days after vaccination to 21.4% (95% CI: -57.4-60.8) at season end. To assess if vaccination campaign strategies need revising more evidence on VE by time since vaccination is urgently needed.
authors.affiliation: EpiConcept, Paris, France.
authors.forename: Esther
authors.initials: E
authors.lastname: Kissling
authors.forename: Baltazar
authors.initials: B
authors.lastname: Nunes
authors.forename: Chris
authors.initials: C
authors.lastname: Robertson
authors.forename: Marta
authors.initials: M
authors.lastname: Valenciano
authors.forename: Annicka
authors.initials: A
authors.lastname: Reuss
authors.forename: Amparo
authors.initials: A
authors.lastname: Larrauri
authors.forename: Jean Marie
authors.initials: JM
authors.lastname: Cohen
authors.forename: Beatrix
authors.initials: B
authors.lastname: Oroszi
authors.forename: Caterina
authors.initials: C
authors.lastname: Rizzo
authors.forename: Ausenda
authors.initials: A
authors.lastname: Machado
authors.forename: Daniela
authors.initials: D
authors.lastname: Pitigoi
authors.forename: Lisa
authors.initials: L
authors.lastname: Domegan
authors.forename: Iwona
authors.initials: I
authors.lastname: Paradowska-Stankiewicz
authors.forename: Udo
authors.initials: U
authors.lastname: Buchholz
authors.forename: Alin
authors.initials: A
authors.lastname: Gherasim
authors.forename: Isabelle
authors.initials: I
authors.lastname: Daviaud
authors.forename: Judit Krisztina
authors.initials: JK
authors.lastname: Horváth
authors.forename: Antonino
authors.initials: A
authors.lastname: Bella
authors.forename: Emilia
authors.initials: E
authors.lastname: Lupulescu
authors.forename: Joan
authors.initials: J
authors.lastname: O Donnell
authors.forename: Monika
authors.initials: M
authors.lastname: Korczyńska
authors.forename: Alain
authors.initials: A
authors.lastname: Moren
mesh_terms: D016022:Case-Control Studies; D004196:Disease Outbreaks / Q000517:prevention & control / Q000706:statistics & numerical data*; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D016896:Treatment Outcome; D014611:Vaccination / Q000706:statistics & numerical data*
chemical_list: D007252:Influenza Vaccines
keywords: Influenza; influenza virus; vaccine-preventable diseases; vaccines and immunisation