As of early May 2026, the Centers for Disease Control and Prevention has confirmed 1,842 measles cases across 39 U.S. jurisdictions, with 93% linked to 25 ongoing outbreaks and 92% occurring in individuals who are unvaccinated or have unknown vaccination status. This surge, already outpacing the full-year 2025 total in several states including Utah and South Carolina, stems primarily from sustained transmission in underimmunized communities following measles introductions via international travel. Official data show low hospitalization rates so far but highlight risks of further spread during summer travel peaks. Traders are monitoring weekly CDC surveillance updates and any shifts in state-level outbreak containment, as case thresholds and elimination-status reviews could alter market resolution by year-end.