title: Predictors of the uptake of A (H1N1) influenza vaccine: findings from a population-based longitudinal study in Tokyo.
abstract: BACKGROUND
  Overall pandemic A (H1N1) influenza vaccination rates remain low across all nations, including Japan. To increase the rates, it is important to understand the motives and barriers for the acceptance of the vaccine. We conducted this study to determine potential predictors of the uptake of A (H1N1) influenza vaccine in a cohort of Japanese general population.
  
  
  RESULTS
  By using self-administered questionnaires, this population-based longitudinal study was conducted from October 2009 to April 2010 among 428 adults aged 18-65 years randomly selected from each household residing in four wards and one city in Tokyo. Multiple logistic regression analyses were performed. Of total, 38.1% of participants received seasonal influenza vaccine during the preceding season, 57.0% had willingness to accept A (H1N1) influenza vaccine at baseline, and 12.1% had received A (H1N1) influenza vaccine by the time of follow-up. After adjustment for potential confounding variables, people who had been vaccinated were significantly more likely to be living with an underlying disease (p = 0.001), to perceive high susceptibility to influenza (p = 0.03), to have willingness to pay even if the vaccine costs ≥ US$44 (p = 0.04), to have received seasonal influenza vaccine during the preceding season (p<0.001), and to have willingness to accept A (H1N1) influenza vaccine at baseline (p<0.001) compared to those who had not been vaccinated.
  
  
  CONCLUSIONS
  While studies have reported high rates of willingness to receive A (H1N1) influenza vaccine, these rates may not transpire in the actual practices. The uptake of the vaccine may be determined by several potential factors such as perceived susceptibility to influenza and sensitivity to vaccination cost in general population.
authors.affiliation: Department of Epidemiology and International Health, National Center for Global Health and Medicine, Tokyo, Japan. siyan@doctor.com
authors.forename: Siyan
authors.initials: S
authors.lastname: Yi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nonaka
authors.forename: Marino
authors.initials: M
authors.lastname: Nomoto
authors.forename: Jun
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizoue
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011795:Surveys and Questionnaires; D014041:Tokyo; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines