The Association Between Immunization Information Systems and Immunizations in Children 19-35 Months of Age in the United States.

Abstract

In 2017, only 70.4% of U.S. children ages 19-35 months were up-to-date (UTD) for their routine series of vaccines, a rate that consistently misses the national target of 80%. Recent evidence has demonstrated that those rates are declining. As a result of an under-vaccinated population, vaccine preventable disease outbreaks are becoming more frequent and places vulnerable populations at risk for disease, disability, or death. Contributors to sub-optimal immunization rates include challenges in identifying vaccination needs, incomplete or inaccurate vaccination records, missed opportunities, and vaccine hesitancy among parents and providers. One strategy to improve immunizations in the U.S. is through the utilization of immunization information systems (IISs). Although large investments into their infrastructure, implementation, and operation have led to widespread adoption of IISs by state immunization programs, research evaluating the impacts of these systems on immunizations is still in early stages and has resulted in mixed findings. The purpose of this dissertation is to explore the relationship of IISs on immunizations. Using data from the National Immunization Survey, The IIS Legislative Survey, and the IIS Annual Reports (IISARs), I analyze the association of IIS policies and participation on immunization status in children 19-35 months of age. Following a three-essay format, I utilize a series of multiple logistic and linear regression models to examine the relationship between IIS participation on UTD status and invalid doses, and IIS policies and provider participation on state-level immunization rates. Consistent with the previous literature, my overall findings on IIS participation resulted in mixed findings. While there was little to no association between IIS participation and the odds of a child completing their full vaccines series, I did find a statistically significant relationship between IIS participation and the odds of invalid doses. Further, previous studies found no association between mandate or consent policies on state-level UTD immunization rates. While supporting previous work, I also find a statistically significant interaction between mandate and consent policies as it relates to UTD rates. This work contributes to the literature by expanding what is known about how IIS policies and participation relate to immunization rates. These studies further highlight the dynamic but important relationships between policy, and participation by providers and parents that can inform future immunization improvement strategies.