U.S. Measles Cases Accelerate, Pennsylvania Declares Outbreak Emergency

The U.S. measles outbreak is intensifying, with confirmed cases reaching 4,410 nationwide since the beginning of 2026, according to the latest data from the Centers for Disease Control and Prevention (CDC). Pennsylvania has emerged as the epicenter, reporting at least 1,200 cases and five deaths, prompting state authorities to request urgent assistance from the CDC's Epi-Aid program. Inadequate vaccination coverage is closely linked to the spread, with approximately 96% of infected individuals being unvaccinated or having undocumented vaccination status.