title: Influenza vaccine effectiveness estimates for Western Australia during a period of vaccine and virus strain stability, 2010 to 2012.
abstract: During 2010-2012 the strain composition of the influenza vaccine in the Southern Hemisphere did not change, but the circulating virus type/subtype did. We pooled data for these years from the Western Australian sentinel medical practice surveillance system for influenza to estimate vaccine effectiveness (VE) by influenza virus type and subtype. A case test-negative design was used with VE estimated as (1-odds ratio)×100%. There were 2182 patients included in the analysis across the 3 years studied. The predominant subtype was A/H1pdm09 in 2010 and 2011, and A/H3 in 2012. The overall adjusted VE estimate against all influenza for 2010-2012 was 51% (95% CI: 36, 63). Estimates were highest against A/H1pdm09 at 74% (95% CI: 47, 87), followed by 56% (95% CI: 33, 71) for influenza B and lowest against A/H3 at 39% (95% CI: 13, 57). When analyses were restricted to compare influenza-positive patients with patients who tested positive for a non-influenza virus, overall adjusted VE was 59% (95% CI: 39, 72). These results suggest moderate protection against influenza by vaccination in Western Australia over the period 2010-2012, and are consistent with findings from other settings.
authors.affiliation: PathWest Laboratory Medicine, Perth, WA, Australia.
authors.forename: Avram
authors.initials: A
authors.lastname: Levy
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia. Electronic address: sheena.sullivan@influenzacentre.org.
authors.forename: Sheena G
authors.initials: SG
authors.lastname: Sullivan
authors.affiliation: PathWest Laboratory Medicine, Perth, WA, Australia.
authors.forename: Simone S
authors.initials: SS
authors.lastname: Tempone
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Kerry L M
authors.initials: KL
authors.lastname: Wong
authors.affiliation: Department of Health (Western Australia), Perth, WA, Australia.
authors.forename: Annette K
authors.initials: AK
authors.lastname: Regan
authors.affiliation: Department of Health (Western Australia), Perth, WA, Australia.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Dowse
authors.affiliation: Department of Health (Western Australia), Perth, WA, Australia.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Effler
authors.affiliation: PathWest Laboratory Medicine, Perth, WA, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D009981:Influenza B virus; D007252:Influenza Vaccines / Q000276:immunology / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018571:Sentinel Surveillance; D014904:Western Australia / Q000453:epidemiology; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines
keywords: Data pooling; Influenza; Influenza season; Influenza vaccine; Influenza-like illness; Vaccine effectiveness