title: Effectiveness of the influenza vaccine at preventing hospitalization due to acute exacerbation of cardiopulmonary disease in Korea from 2011 to 2012.
abstract: There is a lack of targeted studies to validate the effectiveness of influenza vaccination on the reduction in influenza-related hospitalizations among patients with co-morbidities. In this study, we estimate the effectiveness of influenza vaccination on preventing hospitalizations in persons with cardiopulmonary disease and establish an evidence base for recommendations on influenza vaccination in this population. During the influenza epidemic in 2011-2012, we performed a multicenter, retrospective case-control study. Cases were patients hospitalized due to acute exacerbation of asthma, COPD, ischemic heart disease (IHD), and congestive heart failure (CHF). Controls were selected from outpatients who visited study hospitals but who were not hospitalized. Cases and controls were matched 1:1 based on age, gender, and date of hospital visit. Conditional logistic regression analyses were used to determine the effectiveness of vaccination. Between 25 December 2011 and 5 May 2012, 828 of each hospitalized and control subjects were identified. The influenza vaccination rate of the hospitalized and non-hospitalized patients was 54.2% and 60.4%, respectively (P = 0.006). The overall vaccine effectiveness for preventing hospitalization was 33.7% (95% confidence interval [CI] 14.0-49.0%; P = 0.002). Conditional logistic regression analysis showed that influenza vaccination significantly reduced the risk of hospitalization, especially due to acute exacerbation of IHD and CHF, in patients aged 65 y and older. The estimated vaccine effectiveness in these patients was 56.0% (95% CI 32.1-71.4%, P = 0.002). Influenza vaccination was associated with a reduction in the risk of hospitalization due to acute exacerbation of cardiopulmonary disease. We recommend the vaccine be given primarily to patients with underlying cardiovascular disease, particularly those 65 y of age and older.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine; Seoul, South Korea.
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine; Seoul, South Korea.
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.affiliation: Inha University College of Medicine; Incheon, South Korea.
authors.forename: Ji Hyeon
authors.initials: JH
authors.lastname: Baek
authors.affiliation: Hallym University College of Medicine; Chuncheon, South Korea.
authors.forename: Jacob
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine; Seoul, South Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Inha University College of Medicine; Incheon, South Korea.
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine; Seoul, South Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine; Seoul, South Korea; Transgovernmental Enterprise for Pandemic Influenza in Korea; Seoul, South Korea.
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000453:epidemiology / Q000517:prevention & control*; D016022:Case-Control Studies; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000517:prevention & control*; D006760:Hospitalization; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000517:prevention & control*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment
chemical_list: D007252:Influenza Vaccines
keywords: cardiopulmonary disease; effectiveness; hospitalization; influenza vaccine