The US Centers for Disease Control and Prevention (CDC) on Friday reported 4,852 measles cases in the country as of October 29, up 264 cases from its previous update.

Nationwide, hospitalizations linked to measles this year stood at 511 —representing 11 percent of all reported cases r— according to the CDC

People aged 5–19 years accounted for 2,010 cases, followed by 1,996 cases among adults aged 20 and older and 812 cases in children under 5.

The vast majority of infections were among individuals who were unvaccinated or whose vaccination status was unknown, accounting for 96 percent of cases in 2026, up from 93 percent in 2025.

A significant driver of the national surge remains Pennsylvania, which is battling its worst measles outbreak in years. As of October 30, the Pennsylvania Department of Health reported 1,426 measles cases and 268 hospitalizations—rising from 1,398 cases and 265 hospitalizations reported just two days earlier on Wednesday.

Earlier CDC figures from October 22 showed Pennsylvania accounting for 1,327 of the nation's 4,588 cases at that time.

The outbreak has also raised scrutiny over measles-related fatalities. The Pennsylvania state health department has reported five measles-related deaths so far in 2026. However, the CDC has confirmed only three measles-associated deaths nationwide and has not specified where they occurred.

In response to the escalating numbers in the state, the CDC previously announced it would deploy additional support to Pennsylvania to assist local officials in investigating and containing the outbreak.