US Measles Cases Hit 35-Year High With 2,318 Confirmed in 2026

The United States recorded 2,318 confirmed measles cases through July 23, 2026, surpassing the 2,289 cases reported during all of 2025 and reaching the highest level since 1991.

Public health officials say declining childhood vaccination rates are the primary driver. National MMR vaccination rates among kindergartners dropped from 95.2 percent in the 2019-2020 school year to 92.5 percent in 2024-2025. When coverage falls below 95 percent, communities lose herd immunity against measles, one of the most contagious diseases known to medicine.

The CDC reports that 93 percent of 2026 cases involve individuals who are either unvaccinated or have an unknown vaccination status. Researchers say vaccine hesitancy has grown since the COVID-19 pandemic, fueled by misinformation and an increase in non-medical exemptions.

Cases have been reported across 45 jurisdictions. Major outbreaks have affected South Carolina, Utah, Arizona, and Pennsylvania. The CDC has identified 35 new outbreaks this year. No deaths have been reported in 2026, compared to three deaths in 2025.

Public health officials acknowledge that official case counts are likely underestimates. Many individuals may not seek medical treatment or testing, and reporting requirements for hospitalizations vary by state.

The United States declared measles eliminated in 2000. International health officials are scheduled to meet in November 2026 to assess whether the US still meets the criteria for measles-free status. Losing that designation would mark a significant setback for American public health.

Managing the outbreaks is labor-intensive, requiring extensive contact tracing and community outreach. Local health departments are struggling with resource constraints.