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.

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

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2026年7月23日

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Wei Lin,
Seyed M. Mirsattari

摘要

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.