As of early May 2026, the CDC has confirmed 1,842 measles cases nationwide, with 93 percent outbreak-associated across 25 new clusters and persistent transmission from 2025 outbreaks in states including Utah and Arizona. Most infections occur among unvaccinated individuals or those with unknown status, fueled by international travel introductions into under-immunized communities where herd immunity thresholds are not met. This pace already exceeds the full-year totals from low-incidence periods like 2024, reflecting measles' high R0 and rapid airborne spread. Ongoing CDC weekly surveillance reports, state health department updates, and assessments of U.S. elimination status—last threatened in 2019—will shape trader views on whether case counts accelerate through summer travel or decline with targeted vaccination efforts.