title: Interim estimates of 2015/16 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, February 2016.
abstract: Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network (SPSN) assessed interim 2015/16 vaccine effectiveness (VE) against influenza A(H1N1)pdm09 viruses. Adjusted VE showed significant protection of 64% (95% confidence interval (CI): 44-77%) overall and 56% (95%CI: 26-73%) for adults between 20 and 64 years-old against medically attended, laboratory-confirmed A(H1N1)pdm09 illness. Among the 67 A(H1N1)pdm09-positive specimens that were successfully sequenced, 62 (> 90%) belonged to the emerging genetic 6B.1 subclade, defined by S162N (potential gain of glycosylation) and I216T mutations in the haemagglutinin protein. Findings from the Canadian SPSN indicate that the 2015/16 northern hemisphere vaccine provided significant protection against A(H1N1)pdm09 illness despite genetic evolution in circulating viruses.
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, Canada.
authors.forename: Catharine
authors.initials: C
authors.lastname: Chambers
authors.forename: Danuta M
authors.initials: DM
authors.lastname: Skowronski
authors.forename: Suzana
authors.initials: S
authors.lastname: Sabaiduc
authors.forename: Anne Luise
authors.initials: AL
authors.lastname: Winter
authors.forename: James A
authors.initials: JA
authors.lastname: Dickinson
authors.forename: Gaston
authors.initials: G
authors.lastname: De Serres
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Gubbay
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Drews
authors.forename: Christine
authors.initials: C
authors.lastname: Martineau
authors.forename: Alireza
authors.initials: A
authors.lastname: Eshaghi
authors.forename: Mel
authors.initials: M
authors.lastname: Krajden
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bastien
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D018571:Sentinel Surveillance; D014611:Vaccination / Q000706:statistics & numerical data; D064166:Vaccine Potency
chemical_list: D007252:Influenza Vaccines
keywords: effectiveness; influenza; influenza virus; influenza-like illness - ILI; vaccine-preventable diseases; vaccines and immunisation