Political polarization, educational attainment, and childhood vaccination coverage in the United States, 2014–2024: a cross-sectional study

Introduction Childhood vaccination coverage in the United States has declined in recent years, raising concern about the reemergence of vaccine-preventable diseases. We examined whether state-level political partisanship was associated with routine childhood vaccination coverage after adjustment for socioeconomic factors from 2014 to 2024. Methods We conducted a cross-sectional ecological study using publicly available state-level panel data from 50 states and the District of Columbia from 2014 to 2024. The analytic panel included 561 state-year observations. The primary outcome was measles-mumps-rubella coverage; secondary outcomes were diphtheria-tetanus-acellular pertussis, poliovirus, and hepatitis B coverage. Multivariable ordinary least squares regression with year fixed effects, Welch t tests, analysis of variance, and interaction models were used. Data were analyzed in March 2026. Sensitivity analyses included two-way (state and year) fixed-effects specifications, persistence-classification subset models (states with consistent presidential vote outcomes across multiple elections), and county-level analyses. Results Blue states had higher mean measles-mumps-rubella (MMR) vaccination coverage than red states (89.69% vs. 87.34%), a difference of 2.35% points ( P <.001). In adjusted analyses with racial composition included as a covariate, higher Republican presidential vote share was associated with lower MMR vaccination coverage (b=-10.90; 95% CI=-16.69, -5.10; P <.001; n = 406 state-year observations). Every 10-percentage-point increase in Republican vote share corresponded to approximately 1.09%-point lower MMR vaccination coverage. Political-educational strata differed in coverage (analysis of variance P <.001), and the political association did not strengthen over time (interaction P =.38). Persistence-based sensitivity analyses among states with consistent presidential vote outcomes across four elections (2012–2024) and three elections (2016–2024) yielded strengthened associations (b=-14.30, P <.001, n = 326; and b=-13.17, P <.001, n = 350, respectively). Within-state county-level analyses (county fixed effects and state-stratified specifications) were directionally consistent with the state-level finding ( n = 411 county-year observations from a 2023 cross-section across four states). Conclusions State-level political context was associated with vaccination coverage after socioeconomic adjustment. Immunization surveillance, communication, and outreach strategies may benefit from accounting for undercoverage risk.