Spatial accessibility to providers and vaccination compliance among children with medicaid.

OBJECTIVE We examined the relationship between spatial accessibility to pediatric immunization providers and vaccination compliance in a low-income, urban population of children. METHODS In 2007, we accessed the Washington, DC, Immunization Information System (IIS) to collect data on the immunization statuses and residential addresses of children who were aged 19 to 35 months and had Medicaid insurance. In addition, we calculated each child's spatial accessibility to pediatric vaccination providers by assessing the provider-to-population ratio at each residential address. Spatial accessibility was divided into tertiles (low, medium, and high) of access. The relationship between spatial accessibility to providers and vaccination compliance was examined by using logistic regression analysis adjusting for age, type of vaccination provider, and enrollment in child care status. RESULTS Overall for our cohort of 4195 children, 80.5% of the children were up-to-date with vaccinations. Vaccination coverage ranged from 61.6% to 100% (median: 79.2%) among different neighborhoods. Having the highest level of access to pediatric vaccination providers was associated with 36% higher odds of being up-to-date as compared with having the lowest level of access. The middle tertile of access was associated with 25% higher odds of being up-to-date. CONCLUSIONS Within our low-income, urban population, children with higher spatial accessibility to pediatric vaccination providers were more likely to be up-to-date with vaccinations. This association may guide future studies and efforts to ensure adequate immunization coverage for children regardless of where they live.