Vaccination remains one of the most effective public health tools globally. Yet recent years have seen increasing political polarization around vaccination, particularly in the United States, as well as measles outbreaks among unvaccinated children. Using individual-level data, we characterize the national evolution of parental political polarization in childhood vaccination refusal, timely receipt of a child’s first measles, mumps, and rubella (MMR) dose, and delay in first MMR vaccination.
This study provides the first nationwide, individual-level evidence linking parental political affiliation to vaccine refusal rates, MMR vaccination rates, and MMR vaccination delays. Despite various data limitations, our finding of the emergence and widening of partisan gaps over time suggests that political identity has become an increasingly important factor in childhood health decision-making.