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.