title: Effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2013.
abstract: This study reports the first vaccine effectiveness (VE) estimates for the prevention of general practice visits and hospitalisations for laboratory-confirmed influenza from an urban population in Auckland, New Zealand, in the same influenza season (2013). A case test-negative design was used to estimate propensity-adjusted VE in both hospital and community settings. Patients with a severe acute respiratory infection (SARI) or influenza-like illness (ILI) were defined as requiring hospitalisation (SARI) or attending a general practice (ILI) with a history of fever or measured temperature ≥38 °C, cough and onset within the past 10 days. Those who tested positive for influenza virus were cases while those who tested negative were controls. Results were analysed to 7 days post symptom onset and adjusted for the propensity to be vaccinated and the timing during the influenza season. Influenza vaccination provided 52% (95% CI: 32 to 66) protection against laboratory-confirmed influenza hospitalisation and 56% (95% CI: 34 to 70) against presenting to general practice with influenza. VE estimates were similar for all types and subtypes. This study found moderate effectiveness of influenza vaccine against medically attended and hospitalised influenza in New Zealand, a temperate, southern hemisphere country during the 2013 winter season.
authors.affiliation: The University of Auckland, Auckland, New Zealand.
authors.forename: N
authors.initials: N
authors.lastname: Turner
authors.forename: N
authors.initials: N
authors.lastname: Pierse
authors.forename: A
authors.initials: A
authors.lastname: Bissielo
authors.forename: Qs
authors.initials: Q
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Radke
authors.forename: Mg
authors.initials: M
authors.lastname: Baker
authors.forename: Ma
authors.initials: M
authors.lastname: Widdowson
authors.forename: H
authors.initials: H
authors.lastname: Kelly
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009520:New Zealand; D011320:Primary Health Care; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D018571:Sentinel Surveillance; D014505:Urban Population / Q000706:statistics & numerical data; D014611:Vaccination; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines