As of mid-May 2026, the United States has recorded 1,842 confirmed measles cases, with 93% linked to ongoing outbreaks that began in 2025 and 25 new clusters reported this year across 39 jurisdictions. Primary drivers include sustained transmission in under-vaccinated communities—where over 90% of cases involve individuals with unknown or zero MMR doses—combined with imported infections from global hotspots. The CDC notes that most cases remain outbreak-associated rather than sporadic travel-related, while summer travel windows could accelerate further spread. Historical precedent shows elimination status at risk when annual totals exceed roughly 1,000–1,300, as occurred in 2019; weekly CDC surveillance updates through summer will determine whether case counts stabilize or accelerate toward a new record.