The Centers for Disease Control and Prevention reported 1,362 confirmed measles cases nationwide in 2026, with 94% linked to ongoing outbreaks. South Carolina's outbreak, which began in October 2025, has decelerated to approximately 10 cases per week after peaking at 200 weekly cases in mid-January, bringing the state total to 996 cases as of March 13. Utah's outbreak, originating in June 2025, has accelerated to 405 cases as of March 10, representing a 47-case increase in one week. Both states currently host the largest active measles outbreaks in the United States.