Factors affecting repeated influenza vaccination among elderly in Taiwan.

[[abstract]]Objective This study identifies factors that influence repeated influenza vaccination among people aged 65 years and older in Taiwan. Methods Data of this retrospective cohort study were drawn from the 2005 National Health Interview Survey and the 2005–2007 National Health Insurance claims data; a sample of 1384 older people was analyzed. The pattern of repeated influenza vaccination was divided into 3 groups: unvaccinated all 3 years, vaccinated 1–2 times over 3 years, and vaccinated all 3 years. Multinomial logistic regression analyses were performed. Results Only 20.6% of older people were vaccinated all 3 years. Those 70–74 years of age (odds ratio [OR] = 1.81), living in rural areas (OR = 2.47), having one (OR = 2.07) or more (OR = 2.41) chronic conditions, frequent outpatient visits (OR = 1.48), and undergoing preventive health examinations (OR = 2.22) were more likely to have repeated vaccinations. However, those with difficulties performing one or more activities of daily living (ADL difficulty) (OR = 0.41) and seeking care from alternative medicine (OR = 0.48) were less likely to undergo regular vaccinations. Conclusion The repeated influenza vaccination rates in our Taiwan sample were far from optimal. Factors identified in this analysis may help to improving influenza vaccination programs