A Socioecological Exploration of County-Level Toddler Immunization Completion

Abstract

There is wide variation among county-level toddler immunization completion, which ranges from 26% to more than 90%. The cause of this variation is unclear and reflects our limited understanding of the factors that affect toddler immunization. Aims. 1) Identify a theoretical framework to support the multifaceted nature of toddler immunization completion research. 2) Describe the characteristics of counties with high and low toddler immunization completion. 3) Explore relationships between county-level toddler immunization completion and immunization-related state policies. Methods. Theoretical arguments proposed by Rose (1985) were used to adapt the ecological systems theory for populations instead of individuals. A cross-sectional sample of 624 counties from 10 states was then used in a secondary data analysis exploring county-characteristics associated with toddler immunization completion. The same sample was then used to explore the association between county-level toddler immunization coverage and state policies. Results. 1) A socioecological framework was identified and modified. 2) There are county characteristics positively and negatively associated with county-level toddler immunization completion. 3) Counties in states that expanded Medicaid or had Democratic legislatures had lower toddler immunization completion. Conclusion. Complex, local-level characteristics have a relationship with variation in county-level toddler immunization completion. Understanding these relationships can help researchers, policy makers, and public health professionals take important actions that can help improve immunization rates.