Social determinants of pneumococcal vaccination status in Japanese elders

Introduction Pneumonia is a major cause of mortality in older adults and pneumococcus is one of the most important pathogens resulting in pneumonia in this population. Although pneumococcal vaccine is available in many countries, vaccine coverage is low, especially in developing countries. In Japan, a regular immunization program for older adults was begun in 2014. We investigated the social determinants of pneumococcal vaccination in older Japanese adults. Methods We analyzed data from the Japan Gerontological Evaluation Study (JAGES), a self-administered postal survey of community-dwelling adults aged 65 years or older. Pneumococcal vaccination status was ascertained by means of the question, “Have you been vaccinated for pneumococcus within the previous 5 years?”. Multilevel Poisson regression was used to examine associations of individual socioeconomic status and municipal subsidization for pneumococcal vaccination with vaccination status, after adjustment for age, self-rated health, underlying respiratory diseases, and living arrangement. Results Among the 166,776 respondents (76,944 men and 89,839 women) in 39 Japanese municipalities, 43.3% (72,274) had been vaccinated during the previous 5 years. Men were more likely than women to have been vaccinated (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.22–1.27). As compared with elders aged 65–69 years, older elders were significantly more likely to have been vaccinated (OR [95% CI]: 1.52 [1.47–1.56] for age 70–74 years, 2.37 [2.29–2.44] for age 75–79 years, 3.00 [2.89–3.12] for age 80–84 years, and 2.98 [2.84–3.13] for age 85 years or older). As compared with elders with incomes less than 0.5 million yen, those with higher equivalent incomes were significantly more likely to have been vaccinated (OR [95% CI]: 1.13 [1.05–1.22] for 1–1.99 million yen, 1.32 [1.23–1.42] for 2–3.99 million yen, and 1.42 [1.31–1.54] for 4 million yen or more). As compared with elders with less than 6 years of education, those with greater educational attainment were significantly more likely to have been vaccinated (OR [95% CI]: 1.39 [1.23–1.58] for 6–9 years, 1.63 [1.44–1.85] for 10–12 years, and 1.67 [1.47–1.89] for 13 or more years). Municipal subsidization for pneumococcal vaccination was not significantly associated with immunization status. Conclusions Immunization behavior in older adults was significantly associated with individual socioeconomic status but not with municipal subsidization for pneumococcal vaccination.