Partisan Polarization of Childhood Vaccination Policies, 1995‒2020.

To examine trends in partisan polarization of childhood vaccine bills and the impact of polarization on bill passage in the United States. We performed content analysis on 1497 US state bills (1995-2020) and obtained voting returns for 228 legislative votes (2011‒2020). We performed descriptive and statistical analyses using 2 measures of polarization.

Neighborhood political composition and personal belief exemptions from immunization requirements in California Kindergartens, 2000-2015.

Introduction: The growing proportion of parents filing personal belief exemptions (PBEs) from school-based vaccine requirements, and the clustering of PBEs in particular schools and communities, could weaken herd immunity and increase vaccine-preventable disease. Alignment of vaccine opposition with a particular political party or ideology could substantially increase PBEs. This study extends our understanding of the link between vaccine refusal and politics by identifying longitudinal associations between neighborhood political composition and school-level prevalence of PBEs between 2000 and 2015 in California.