Ongoing measles outbreaks driven by pockets of low vaccination coverage continue to shape trader sentiment on total U.S. cases for 2026. As of May 7, the CDC has confirmed 1,842 cases, already surpassing the pace of 2025’s full-year total of 2,288 and marking the highest early-year activity since elimination status was achieved in 2000. Ninety-three percent of cases are outbreak-associated, with the largest clusters in South Carolina, Utah, Texas, and Florida, where 72 percent involve children and adolescents. Most infections occur in unvaccinated individuals or those with unknown status, consistent with historical patterns when MMR coverage falls below the 95 percent herd-immunity threshold. Weekly CDC surveillance updates and state health department reports through summer will provide the next data points traders monitor for resolution criteria on annual totals.