As of October 1, 2026, the CDC has confirmed 3,887 measles cases across 47 jurisdictions, already far exceeding the full-year 2025 total of 2,289 and marking the highest annual count since 1991. Primary drivers include record kindergarten MMR exemption rates of 4.2% for the 2025–2026 school year, with 95% of 2026 cases occurring in unvaccinated or unknown-status individuals and 95% linked to 42 ongoing outbreaks. Most cases affect school-age children, and hospitalizations stand at 9%. Weekly CDC surveillance updates, ongoing state reporting, and the Pan American Health Organization’s November 2026 review of U.S. elimination status represent key near-term data points that could shift trader assessments of final 2026 totals.