Assessing the distribution and drivers of vaccine hesitancy using medical claims data

Introduction In the United States, surveillance of vaccine uptake for childhood infections is limited in scope and spatial resolution. The National Immunization Survey (NIS) the gold standard tool for monitoring vaccine uptake among children aged 19-35 months is typically constrained to producing coarse state-level estimates.1 In recent years, vaccine hesitancy (i.e., a desire to delay or refuse vaccination, despite availability of vaccination services)2 has resurged in the United States, challenging the maintenance of herd immunity. In December 2014, foreign importation of the measles virus to Disney theme parks in Orange County, California resulted in an outbreak of 111 measles cases, 45% of which were among unvaccinated individuals.3 Digital health data offer new opportunities to study the social determinants of vaccine hesitancy in the United States and identify finer spatial resolution clusters of under-immunization using data with greater clinical accuracy and rationale for hesitancy.4