title: Case-control study of the effectiveness of the 2010-2011 seasonal influenza vaccine for prevention of laboratory-confirmed influenza virus infection in the Korean adult population.
abstract: We evaluated the effectiveness of the 2010-2011 seasonal influenza vaccine for preventing laboratory-confirmed influenza in a South Korean population. A retrospective case-control study was conducted among patients who visited selected hospitals from September 2010 to May 2011. A total of 483 laboratory-confirmed influenza patients were included in the analysis as case subjects. For each case patient, two types of control patients were chosen at a ratio of 1:1:1, and 966 control subjects were selected. Vaccine effectiveness (VE) was defined as 100 × (1 - odds ratio for influenza in vaccinated versus nonvaccinated persons). The VE of the 2010-2011 seasonal influenza vaccine was 49.5% to 45.8% for both influenza A and B viruses and 50.8% to 47.2% for influenza A virus, according to the control type. The age-specific adjusted VE was 50.8% to 46.5% among subjects aged 19 to 49 years and 58.7% to 63.3% among those aged 50 to 64 years, according to the control type. Statistically significant VE was not found among those aged ≥65 years or against influenza B virus. The 2010-2011 seasonal influenza vaccine was effective for preventing laboratory-confirmed influenza, especially for influenza A virus, in a South Korean population. Evidence of the effectiveness of the influenza vaccine in older adults or against influenza B virus was not found.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.forename: Ji Hyeon
authors.initials: JH
authors.lastname: Baek
authors.forename: Jacob
authors.initials: J
authors.lastname: Lee
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Park
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000276:immunology; D009981:Influenza B virus / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D007252:Influenza Vaccines