Outbreak Slows

• Florida reported 143 measles cases as of March 21, 2026, with 73% concentrated in Collier County, marking a decline from 139 cases the previous week. • The state has dropped to the fourth-highest number of measles cases nationally as the spread slows, indicating a shift in outbreak trajectory. • The majority of cases remain geographically concentrated, with nearly three-quarters of infections occurring in a single county, suggesting localized transmission patterns.

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.

A major measles outbreak in South Carolina is showing signs of slowing, with cases nearing 1,000 total and new infections dropping to about 10 per week from a peak of 200 weekly in mid-January. State health officials report a consistent downward trend over several weeks amid vaccination efforts. The decline matters as it reduces strain on public health resources in a state hit hardest by the outbreak. Monitoring continues to prevent resurgence through summer.