Retrospective assessment of influenza vaccine effectiveness among the non-institutionalized elderly population in Japan.
To construct a framework for monitoring the effectiveness of influenza vaccine, we retrospectively surveyed elderly (> or = 65 years old) people living in rural areas of Kyoto prefecture, Japan, using a self-administered questionnaire, for their influenza-related symptoms during the peak influenza season of 2003-2004. A total of 2301 elderly individuals responded, of whom 1533 (66.6%) had been vaccinated. The odds ratio (OR) of vaccination for fever of > or = 38 degrees C, adjusted for sex, age and underlying conditions, was 0.77 (95% confidence interval (CI), 0.40-1.47), and the OR for a diagnosis of influenza in clinics was 0.81 (95% CI, 0.41-1.57). These findings suggested that the vaccine was 20% effective, although this effectiveness was not statistically significant.
Ozasa
Kotaro
K
Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine Graduate School of Medical Science, 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan. kozasa@koto.kpu-m.ac.jp
Kawahito
Yutaka
Y
Doi
Takashi
T
Watanabe
Yoshiyuki
Y
Washio
Masakazu
M
Mori
Mitsuru
M
Kase
Tetsuo
T
Maeda
Akiko
A
Hirota
Yoshio
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000096:biosynthesis; D003625:Data Collection; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012111:Residence Characteristics; D012189:Retrospective Studies; D014611:Vaccination / Q000706:statistics & numerical data*
D000914:Antibodies, Viral; D007252:Influenza Vaccines