Factors affecting repeated influenza vaccination among older people in Taiwan

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.