Early season co-circulation of influenza A(H3N2) and B(Yamagata): interim estimates of 2017/18 vaccine effectiveness, Canada, January 2018

Using a test-negative design, we assessed interim vaccine effectiveness (VE) for the 2017/18 epidemic of co-circulating influenza A(H3N2) and B(Yamagata) viruses. Adjusted VE for influenza A(H3N2), driven by a predominant subgroup of clade 3C.2a viruses with T131K + R142K + R261Q substitutions, was low at 17% (95% confidence interval (CI): -14 to 40). Adjusted VE for influenza B was higher at 55% (95% CI: 38 to 68) despite prominent use of trivalent vaccine containing lineage-mismatched influenza B(Victoria) antigen, suggesting cross-lineage protection.
Authors (Zotero)
Skowronski, Danuta M.; Chambers, Catharine; De Serres, Gaston; Dickinson, James A.; Winter, Anne-Luise; Hickman, Rebecca; Chan, Tracy; Jassem, Agatha N.; Drews, Steven J.; Charest, Hugues; Gubbay, Jonathan B.; Bastien, Nathalie; Li, Yan; Krajden, Mel
Date (Zotero)
February, 2018