The United States has recorded 4,080 confirmed measles cases in 2026 as of October 10th, according to the latest data from the Centers for Disease Control and Prevention. This marks the highest annual total since 1991 and reflects a sharp increase from the 2,289 cases reported for all of 2025.

Cases have been reported across 47 jurisdictions, including 45 states and the District of Columbia, with Pennsylvania accounting for the largest share at more than 1,100 infections. Other states with significant activity include Wisconsin, Ohio, New York, and Kentucky. Eighteen cases involved international visitors.

Ninety-six percent of the cases are linked to outbreaks, and 95 percent occurred among individuals who were unvaccinated or whose vaccination status was unknown. Two percent of cases involved people who received one dose of the MMR vaccine, and another two percent involved those who received both recommended doses.

Hospitalizations reached 414, or 10 percent of total cases. Children under age 5 accounted for 17 percent of infections, while those aged 5 to 19 represented 42 percent. Adults 20 and older made up 40 percent.

The CDC has confirmed two measles-associated deaths this year, though Pennsylvania health officials have reported five deaths in their state alone. The agency noted that its death count is subject to change and has shifted to using National Center for Health Statistics data for verification.

New York declared a statewide disaster emergency earlier this week due to its outbreak. Health officials continue to emphasize that two doses of the MMR vaccine provide strong protection against the highly contagious virus.