title: Low and decreasing vaccine effectiveness against influenza A(H3) in 2011/12 among vaccination target groups in Europe: results from the I-MOVE multicentre case-control study.
abstract: Within the Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) project we conducted a multicentre case–control study in eight European Union (EU) Member States to estimate the 2011/12 influenza vaccine effectiveness against medically attended influenza-like illness (ILI) laboratory-confirmed as influenza A(H3) among the vaccination target groups. Practitioners systematically selected ILI / acute respiratory infection patients to swab within seven days of symptom onset. We restricted the study population to those meeting the EU ILI case definition and compared influenza A(H3) positive to influenza laboratory-negative patients. We used logistic regression with study site as fixed effect and calculated adjusted influenza vaccine effectiveness (IVE), controlling for potential confounders (age group, sex, month of symptom onset, chronic diseases and related hospitalisations, number of practitioner visits in the previous year). Adjusted IVE was 25% (95% confidence intervals (CI): -6 to 47) among all ages (n=1,014), 63% (95% CI: 26 to 82) in adults aged between 15 and 59 years and 15% (95% CI: -33 to 46) among those aged 60 years and above. Adjusted IVE was 38% (95%CI: -8 to 65) in the early influenza season (up to week 6 of 2012) and -1% (95% CI: -60 to 37) in the late phase. The results suggested a low adjusted IVE in 2011/12. The lower IVE in the late season could be due to virus changes through the season or waning immunity. Virological surveillance should be enhanced to quantify change over time and understand its relation with duration of immunological protection. Seasonal influenza vaccines should be improved to achieve acceptable levels of protection.
authors: EpiConcept, Paris, France. e.kissling@epiconcept.fr
authors: E
authors: E
authors: Kissling
authors: M
authors: M
authors: Valenciano
authors: A
authors: A
authors: Larrauri
authors: B
authors: B
authors: Oroszi
authors: J M
authors: JM
authors: Cohen
authors: B
authors: B
authors: Nunes
authors: D
authors: D
authors: Pitigoi
authors: C
authors: C
authors: Rizzo
authors: J
authors: J
authors: Rebolledo
authors: I
authors: I
authors: Paradowska-Stankiewicz
authors: S
authors: S
authors: Jiménez-Jorge
authors: J K
authors: JK
authors: Horváth
authors: I
authors: I
authors: Daviaud
authors: R
authors: R
authors: Guiomar
authors: G
authors: G
authors: Necula
authors: A
authors: A
authors: Bella
authors: J
authors: J
authors: O'Donnell
authors: M
authors: M
authors: Głuchowska
authors: B C
authors: BC
authors: Ciancio
authors: A
authors: A
authors: Nicoll
authors: A
authors: A
authors: Moren
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005060:Europe / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology* / Q000302:isolation & purification; D053123:Influenza A Virus, H3N8 Subtype / Q000276:immunology* / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology; D009666:Nose / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D018571:Sentinel Surveillance; D016896:Treatment Outcome; D014611:Vaccination / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines