Growing Republican mistrust in the healthcare system has widened health disparities between liberals and conservatives, who are more likely to avoid vaccines and the medical system in general, according to a new study. Neil O’Brian, a political science professor at the University of Carolina, Chapel Hill and one of the authors of the study published in Nature Human Behaviour, said that his team saw two phases to the phenomenon.
“Part one is this gap starts to emerge in the 2010s, and it seems like it’s a byproduct of education polarization,” O’Brian explained, “Folks without a college degree move to the right. Folks with a college degree move to the left.
That happens for a variety of reasons. Education is a pretty strong predictor of health.” The second phase began during the Covid-19 pandemic, when social determinants of health, including education, could no longer explain the expanding gap in health outcomes.
“This is a real puzzle,” O’Brian said. “We turn to the survey data and show that people on the right are less likely to trust, engage, or use medicines to treat chronic illness relative to the left.” Past research has found that Republicans’ hesitation to vaccinate against Covid-19 has meant they suffered more death from the pandemic than Democrats.
But O’Brian’s study showed that even different vaccination rates don’t completely explain the difference in health outcomes – a lack of overall trust in the medical system is also contributing. The study relies on survey data collected in 2024 and O’Brian suspects that the health gap has only continued to worsen during the second Trump administration, which began in January 2025.