HATTIESBURG — A study published in Nature Human Behaviour in 2026 found that growing Republican mistrust in the healthcare system has widened health disparities between liberals and conservatives. Researchers reported that Republicans are increasingly avoiding doctors and vaccines, contributing to measurable differences in health outcomes.

The study, based on survey data collected in 2024, identifies two phases in the emergence of this health gap. The first began in the 2010s, linked to education polarization. “Part one is this gap starts to emerge in the 2010s, and it seems like it’s a byproduct of education polarization,” explained Neil O’Brian, a political science professor at the University of North Carolina, Chapel Hill, and one of the study’s authors. “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 accelerated during the Covid-19 pandemic, when social determinants like education no longer fully accounted for the widening gap. “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.” He added, “Folks on the right have more hypertension [or high blood pressure] than the folks on the left, and now people on the Right are less likely to go to their doctor, less likely to trust their doctor, less likely to think medicines to treat hypertension are safe and effective.”

O’Brian said differing vaccination rates alone do not explain the health outcome gap; lack of trust in the medical system also contributes. Past research has found that Republican hesitancy toward Covid-19 vaccination resulted in higher death rates compared to Democrats. Anti-vaccination attitudes have since expanded to include long-established vaccines for diseases like measles, and more red states are repealing vaccine mandates.

Jay Van Bavel, a professor of psychology and neuroscience at New York University, linked the trend to national policy shifts. “What we’re seeing is a continuation and expansion of a lot of the dynamics that happened during the pandemic,” Van Bavel said, noting that “when you elevate someone like RFK Jr to oversee health decisions for the country, now you’re getting all of these things entrenched and embedded in national health policies around vaccination, and so you see a lot of this accelerating really quickly.” He observed that Republicans are more likely to suffer from long Covid due to lower vaccination rates but are also less likely to seek care for it. “What you’re also going to see, however, is that the segment of the society that is more likely to have long Covid because they didn’t get vaccinated is probably least likely to identify themselves as having long Covid or go to the doctor complaining about long Covid,” Van Bavel said.

O’Brian cautioned that while the study ends with 2024 data, he suspects the gap has worsened during the second Trump administration, which began in January 2025—a projection not covered by the study’s findings.