As of late May 2026, the CDC has confirmed nearly 2,000 measles cases in the United States, already approaching last year’s total of 2,288 and marking the highest annual counts since the early 1990s. Primary drivers include sustained community transmission in under-vaccinated populations, where 93% of cases are outbreak-associated and over 90% involve individuals who are unvaccinated or have unknown MMR status, combined with imported infections from international travel. This resurgence threatens the country’s measles elimination status, achieved in 2000, as ongoing outbreaks continue across multiple jurisdictions. Weekly CDC surveillance updates and state-level reporting will provide the key data releases that could shift market-implied odds through summer and fall.