title: No association between 2008-09 influenza vaccine and influenza A(H1N1)pdm09 virus infection, Manitoba, Canada, 2009.
abstract: We conducted a population-based study in Manitoba, Canada, to investigate whether use of inactivated trivalent influenza vaccine (TIV) during the 2008-09 influenza season was associated with subsequent infection with influenza A(H1N1)pdm09 virus during the first wave of the 2009 pandemic. Data were obtained from a provincewide population-based immunization registry and laboratory-based influenza surveillance system. The test-negative case-control study included 831 case-patients with confirmed influenza A(H1N1)pdm09 virus infection and 2,479 controls, participants with test results negative for influenza A and B viruses. For the association of TIV receipt with influenza A(H1N1)pdm09 virus infection, the fully adjusted odds ratio was 1.0 (95% CI 0.7-1.4). Among case-patients, receipt of 2008-09 TIV was associated with a statistically nonsignificant 49% reduction in risk for hospitalization. In agreement with study findings outside Canada, our study in Manitoba indicates that the 2008-09 TIV neither increased nor decreased the risk for infection with influenza A(H1N1)pdm09 virus.
authors.affiliation: University of Manitoba, Winnipeg, Manitoba, Canada. salah.mahmud@gmail.com
authors.forename: Salaheddin M
authors.initials: SM
authors.lastname: Mahmud
authors.forename: Paul
authors.initials: P
authors.lastname: Van Caeseele
authors.forename: Gregory
authors.initials: G
authors.lastname: Hammond
authors.forename: Carol
authors.initials: C
authors.lastname: Kurbis
authors.forename: Tim
authors.initials: T
authors.lastname: Hilderman
authors.forename: Lawrence
authors.initials: L
authors.lastname: Elliott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D058873:Pandemics; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines