US Reports 4,852 Measles Cases in 2026 as Pennsylvania Outbreak Continues to Grow

The United States has recorded 4,852 measles cases so far in 2026, with the Centers for Disease Control and Prevention (CDC) reporting an increase of 264 infections in its latest update released Friday, October 29.

According to the CDC, 511 people have been hospitalized this year, accounting for approximately 11 percent of all reported cases.

Children and young adults continue to account for a substantial share of infections. People aged 5 to 19 years represented 2,010 cases, followed by 1,996 cases among adults aged 20 and older. Children under the age of five accounted for another 812 infections.

The CDC data also showed that the overwhelming majority of cases involved people who were unvaccinated or whose vaccination status was unknown. These groups accounted for 96 percent of infections in 2026, compared with 93 percent in 2025.

Pennsylvania Emerges as a Major Outbreak Hotspot

Pennsylvania remains a significant contributor to the nationwide surge, reporting its worst measles outbreak in years.

As of October 30, the Pennsylvania Department of Health had recorded 1,426 cases and 268 hospitalizations. The figures marked an increase from 1,398 cases and 265 hospitalizations reported just two days earlier, on Wednesday.

Earlier CDC data released on October 22 showed that Pennsylvania accounted for 1,327 of the 4,588 measles cases recorded nationwide at the time.

The growing outbreak has also drawn attention to measles-related fatalities. Pennsylvania health authorities have reported five measles-related deaths in 2026. However, the CDC has confirmed three measles-associated deaths nationwide and has not specified where those fatalities occurred.

CDC Steps Up Support for Pennsylvania

Amid the rising number of infections, the CDC previously announced plans to deploy additional assistance to Pennsylvania to support local health authorities in investigating cases and containing the outbreak.

The escalating figures highlight the continuing public health challenge posed by measles in the United States, particularly as infections remain heavily concentrated among people who are unvaccinated or whose vaccination status has not been established.

Health authorities are continuing to monitor the outbreak and support efforts to limit further transmission.