U.S. Measles Cases Top 4,000 in 2026

The U.S. measles count exceeded 4,000 in August, making 2026 the country’s highest-case year in over three decades. By mid-July, infections had already passed the full-year 2025 total of 2,289 confirmed cases. More than 750 of those 2025 cases were tied to a West Texas outbreak in which two children died.

Two deaths have been recorded in the U.S. this year. Pennsylvania health officials said both occurred in Lancaster County among unvaccinated people. They were the state’s first measles-related deaths in 35 years. Most cases nationwide have involved unvaccinated people, while outbreaks have expanded in communities with lower vaccination levels.

For Simi Valley parents, the national school vaccination figures provide context for who is most vulnerable. About 92.4% of U.S. kindergartners received measles-mumps-rubella shots during the 2025-2026 school year, compared with 92.5% one year earlier and 95.2% in 2019-2020. Only 10 states reached 95% last year, the level associated with community immunity.

Measles spreads extremely easily and can sometimes cause serious brain or lung infections, cognitive problems, deafness or death. Vaccination can prevent the disease, and research supports its safety and effectiveness. Continuing outbreaks could also cost the U.S. its official measles elimination status, held since 2000.