US surpasses 4,000 measles cases with infections confirmed in 45

Most cases are among those unvaccinated or with unknown status, CDC data shows.

Former CDC specialist breaks down largest measles outbreak in 35 years ABC News’ Linsey Davis spoke with Dr. Demetre Daskalakis, former director of the CDC National Center for Immunization & Respiratory Diseases, about the largest measles outbreak in more than 30 years.

Measles cases in the United States have surpassed 4,000 this year, according to data updated Friday from the Centers for Disease Control and Prevention (CDC).

A total of 4,080 cases have been confirmed, with most reported by 45 states and Washington, D.C. Eighteen of this year's total have been among international visitors to the U.S., according to the CDC.

Five measles-associated deaths have been confirmed so far in 2026, all of them in Pennsylvania, according to health officials in the state.

Signs point the way to measles testing in the parking lot of the Seminole Hospital District across from Wigwam Stadium on February 27, 2025 in Seminole, Texas.

The CDC has only recognized two deaths so far this year, with the agency saying that "number is subject to change."

The majority of measles cases in 2026 have been confirmed among children and teenagers aged 19 and younger, according to the CDC. About one in 10 children under age 5 have been hospitalized, CDC data shows.

This is a developing story. Please check back for updates.