title: Effectiveness of trivalent seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: 2012/13 end of season results.
abstract: The effectiveness of the 2012/13 trivalent seasonal influenza vaccine (TIV) was assessed using a test-negative case-control study of patients consulting primary care with influenza-like illness in the United Kingdom. Strain characterisation was undertaken on selected isolates. Vaccine effectiveness (VE) against confirmed influenza A(H3N2), A(H1N1) and B virus infection, adjusted for age, sex, surveillance scheme (i.e. setting) and month of sample collection was 26% (95% confidence interval (CI): -4 to 48), 73% (95% CI: 37 to 89) and 51% (95% CI: 34 to 63) respectively. There was an indication, although not significant, that VE declined by time since vaccination for influenza A(H3N2) (VE 50% within three months, 2% after three months, p=0.25). For influenza A(H3N2) this is the second season of low VE, contributing to the World Health Organization (WHO) recommendation that the 2013/14 influenza vaccine strain composition be changed to an A(H3N2) virus antigenically like cell-propagated prototype 2012/13 vaccine strain (A/Victoria/361/2011). The lower VE seen for type B is consistent with antigenic drift away from the 2012/13 vaccine strain. The majority of influenza B viruses analysed belong to the genetic clade 2 and were antigenically distinguishable from the 2012/13 vaccine virus B/Wisconsin/1/2010 clade 3. These findings supported the change to the WHO recommended influenza B vaccine component for 2013/14.
authors.affiliation: Public Health England Health Protection Directorate, Colindale, London, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Andrews
authors.forename: J
authors.initials: J
authors.lastname: McMenamin
authors.forename: H
authors.initials: H
authors.lastname: Durnall
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.forename: A
authors.initials: A
authors.lastname: Lackenby
authors.forename: C
authors.initials: C
authors.lastname: Robertson
authors.forename: B
authors.initials: B
authors.lastname: von Wissmann
authors.forename: S
authors.initials: S
authors.lastname: Cottrell
authors.forename: B
authors.initials: B
authors.lastname: Smyth
authors.forename: C
authors.initials: C
authors.lastname: Moore
authors.forename: R
authors.initials: R
authors.lastname: Gunson
authors.forename: M
authors.initials: M
authors.lastname: Zambon
authors.forename: D
authors.initials: D
authors.lastname: Fleming
authors.forename: R
authors.initials: R
authors.lastname: Pebody
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D009981:Influenza B virus / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology / Q000627:therapeutic use; D007251:Influenza, Human / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D018571:Sentinel Surveillance; D017422:Sequence Analysis, DNA; D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D007252:Influenza Vaccines