State-Level Variations and Factors Associated with Adult Vaccination Coverage: A Multilevel Modeling Approach

Adult vaccination rates in the USA are generally low and fall short of public health goals. Previous studies have indicated that adult vaccination rates vary between states and that individual characteristics affect vaccination coverage. We used modeling to evaluate the effects of both individual- and state-level factors on adult vaccination coverage. Health insurance coverage, the authority of pharmacists to vaccinate, existence of vaccination exemptions, and immunization information systems adult participation rates had a positive impact on vaccination coverage, although the impact varied by vaccine. These results provide policy decision makers at both state and federal levels with information to consider when expanding vaccination programs or preventive care efforts. However, additional data are needed to further explain the variations between states.