Health status can alter individuals’ social preferences, and specifically individuals' preferences regarding fairness in the access to and financing of health care. We draw on a dataset of 73,452 individuals across 22 countries and a novel instrumental variable strategy that exploits variation in health status resulting from cross-country exposure to the national childhood Bacillus Calmette–Guérin (BCG) vaccination schedules. We document causal evidence consistent with the unhealthy self-interest hypothesis, which indicates that better health increases preferences for a fairer health care system. We estimate that a one-unit increase in self-reported health increases support for fair health care access by 11% and the willingness to support fair financing by 8%. Our findings suggest that improving population health, they may give rise to stronger support for interventions to improve equitable health system access and financing.