Author(s): Skowronski DM, Chambers C, Sabaiduc S, De Serres G, Winter AL,
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Abstract BACKGROUND: Canada's Sentinel Physician Surveillance Network links genetic, antigenic, and vaccine effectiveness (VE) measures in an integrated platform of influenza monitoring, described here for the 2013-2014 influenza season of resurgent A(H1N1)pdm09 and late-season type B activity. METHODS: VE was estimated as [1 - odds ratio] × 100\% and compared vaccination status between individuals who tested positive (cases) and those who tested negative (controls) for influenza virus. Vaccine-virus relatedness was assessed by genomic sequence analysis and hemagglutination inhibition assays. RESULTS: Analyses included 1037 controls (of whom 33\% were vaccinated) and 663 cases (of whom 14\% were vaccinated). A total of 415 cases tested positive for A(H1N1)pdm09 virus, 15 tested positive for A(H3N2) virus, 191 tested positive for B/Yamagata-lineage virus, 6 tested positive for B/Victoria-lineage virus, and 36 tested positive for viruses of unknown subtype or lineage. A(H1N1)pdm09 viruses belonged to clade 6B, distinguished by a K163Q substitution, but remained antigenically similar to the A/California/07/2009-like vaccine strain, with an adjusted VE of 71\% (95\% confidence interval [CI], 58\%-80\%). Most B/Yamagata-lineage viruses (83\%) clustered phylogenetically with the prior (ie, 2012-2013) season's B/Wisconsin/01/2010-like clade 3 vaccine strain, while only 17\% clustered with the current (ie, 2013-2014) season's B/Massachusetts/02/2012-like clade 2 vaccine strain. The adjusted VE for B/Yamagata-lineage virus was 73\% (95\% CI, 57\%-84\%), with a lower VE obtained after partial calendar-time adjustment for clade-mismatched B/Wisconsin/01/2010-like virus (VE, 63\%; 95\% CI, 41\%-77\%), compared with that for clade-matched B/Massachusetts/02/2012-like virus (VE, 88\%; 95\% CI, 48\%-97\%). No A(H3N2) viruses clustered with the A/Texas/50/2012-like clade 3C.1 vaccine strain, and more than half were antigenically mismatched, but sparse data did not support VE estimation. CONCLUSIONS: VE corresponded with antigenically conserved A(H1N1)pdm09 and lineage-matched B/Yamagata viruses with clade-level variation. Surveillance linking genotypic, phenotypic, and epidemiologic measures of vaccine-virus relatedness and effectiveness could better inform predictions of vaccine performance and reformulation. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: firstname.lastname@example.org.
This article was published in J Infect Dis
and referenced in Journal of Vaccines & Vaccination