Selection bias in evaluating of influenza vaccine effectiveness: a lesson from an observational study of elderly nursing home residents.
Selection bias is of critical concern in the study of influenza vaccine effectiveness when using an observational study design. This bias is attributable to the inherently different characteristics between vaccinees and non-vaccinees. The differences, which are related both to vaccination and signs of clinical disease as an outcome, may lead to erroneous estimation of the effectiveness. In this report, we describe how selection bias among elderly nursing home residents may lead to a spurious interpretation of the protective effect of influenza vaccine. Our results should be a lesson in the importance of regarding selection bias when assessing influenza vaccine effectiveness.
Fukushima
Wakaba
W
Department of Public Health, Osaka City University Faculty of Medicine, 1-4-3, Asahi-machi, Osaka 545-8585, Japan. wakaba@med.osaka-cu.ac.jp
Hayashi
Yoshimitsu
Y
Mizuno
Yaichi
Y
Suzuki
Kanzo
K
Kase
Tetsuo
T
Ohfuji
Satoko
S
Fujieda
Megumi
M
Maeda
Akiko
A
Hirota
Yoshio
Y
D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D015331:Cohort Studies; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D009735:Nursing Homes; D012621:Seasons; D016896:Treatment Outcome
D007252:Influenza Vaccines