The United States is experiencing a major resurgence of measles, with the Centers for Disease Control and Prevention (CDC) reporting 3,659 confirmed cases in 2026 as of September 24 and confirming a second measles-related death this year.

The latest figures underline the continuing spread of the highly contagious disease across multiple parts of the country, with outbreaks accounting for the overwhelming majority of confirmed infections.

More Than 3,600 Confirmed Cases

According to the latest CDC update, 3,642 cases were reported by 47 U.S. jurisdictions, while another 17 cases involved international visitors.

The CDC has recorded 40 outbreaks during 2026, and approximately 95% of all confirmed cases are associated with outbreaks.

The current total is already substantially higher than the 2,289 confirmed cases recorded during the whole of 2025. The 2026 figures remain preliminary and can change as health authorities receive and review additional information.

Second Measles-Related Death Confirmed

The CDC confirmed a second measles-related death in the United States on September 29.

The federal count differs from figures reported by Pennsylvania health authorities, which have reported four measles-associated deaths in the state. The difference is connected to how deaths are classified and verified at the federal and state levels.

The CDC has been working with public-health authorities to improve consistency in determining whether a death should be classified as measles-related.

Pennsylvania Remains a Major Outbreak Area

Pennsylvania has been one of the most heavily affected states during the current resurgence.

The state’s measles outbreak had reached 903 cases by September 28, according to state health data, with more than 170 patients requiring hospital treatment.

Other states have also reported significant outbreaks, demonstrating that transmission is not confined to a single region.

Vaccination Coverage Under Focus

Measles is highly contagious, and maintaining high vaccination coverage is an important component of preventing sustained community transmission.

The CDC reports that MMR vaccination coverage among U.S. kindergarten children declined from 95.2% during the 2019–2020 school year to 92.4% during 2025–2026. The agency estimates that about 280,000 kindergarten children were potentially at risk during the 2025–2026 school year.

Health Authorities Continue Monitoring

The CDC and state health departments are continuing to monitor new cases and outbreaks.

The agency is also using wastewater monitoring as an additional tool to understand measles activity at the community level, although such data are intended for surveillance rather than individual diagnosis.

Health authorities are urging continued attention to symptoms, exposure notifications and vaccination status, particularly in communities experiencing active outbreaks.

A Major Public Health Challenge

The rapid increase in measles infections has made 2026 an important year for U.S. infectious-disease surveillance.

The continuing outbreak illustrates how quickly measles can spread when the virus reaches communities with gaps in immunity. With thousands of confirmed cases already recorded and new infections continuing to be reported, public-health agencies remain focused on identifying cases, investigating outbreaks and limiting further transmission.