US measles outbreak hits 35-year high with 2,318 cases in 2026

The United States is experiencing its worst measles outbreak in 35 years, with 2,318 confirmed cases reported so far in 2026, surpassing the record set just last year, according to CDC data Source: Clarin, Excelsior. The highly contagious viral disease, declared eliminated in the US in 2000, has resurged amid declining vaccination rates.

Outbreak details

• Over 93% of cases are in unvaccinated individuals or those with unknown status Source: Infobae. Nearly 70% of cases are in children aged 0-9 Source: Infobae.
• South Carolina leads with 670 cases, including the largest outbreak in decades in Spartanburg County (nearly 1,000 cases from October 2025 to April 2026) Source: CNN, Diario Libre. Utah (518 cases) and Texas (182) follow.
• The outbreak spans 45 jurisdictions, with 35 new outbreaks in 2026, many linked to chains from 2025 Source: Excelsior.

Contributing factors

• Vaccination coverage among kindergarteners dropped from 95.2% (2019-2020) to 92.5% (2024-2025), leaving 286,000 children vulnerable Source: Excelsior, Infobae. Herd immunity requires at least 95% coverage.
• Health Secretary Robert F. Kennedy Jr. has faced criticism for anti-vaccine statements, though evidence supports vaccine safety Source: Clarin, Infobae. "We are witnessing a preventable crisis that disproportionately harms children," said Dr. Andrew Racine, president of the American Academy of Pediatrics Source: Clarin.
• Experts warn actual cases may be much higher due to underdiagnosis and inadequate surveillance Source: Emol. Mathematical models suggest the Utah-Arizona outbreak could be 3-4 times larger than reported Source: Emol.

What's next

• International health officials will meet in November to consider revoking the US measles-free status Source: Emol.
• No deaths have been reported in 2026, compared to three deaths in 2025, including two young children Source: Infobae.
• The CDC continues to report dozens of new cases weekly, and the outbreak is not yet contained Source: CNN.