Pennsylvania measles cases top 900 as outbreak spreads across 39 counties

State health officials reported 903 cases, 176 hospitalizations, and four measles-associated deaths this year; Lancaster County remains the hardest hit.

Confirmed By Alex Rivera · Staff Writer — Health & Climate United States / Pennsylvania Published Sep 28, 2026, 4:35 PM PT Updated Sep 28, 2026, 6:40 PM PT

Pennsylvania’s measles outbreak crossed 900 cases on Monday, with the state Department of Health tallying 903 confirmed infections so far in 2026 after at least 13 new cases since Friday, ABC News (opens in new tab) reported from the department’s update.

Cases have been recorded in 39 of the state’s 67 counties. At least 176 people have been hospitalized, and four measles-associated deaths have been reported: two unvaccinated adults, ages 18 and 40, and two infants too young for the MMR vaccine, according to the department’s figures as reported by ABC News (opens in new tab). Four cases, fewer than 1%, were in fully vaccinated people. In its Sept. 25 release, the department had reported 890 cases and 173 hospitalizations.

Lancaster County leads with 363 cases. Mifflin County has 105 according to ABC News (opens in new tab) (the Inquirer reported 106). The Inquirer described the outbreak as Pennsylvania’s largest in three decades and reported that it has spread into the Philadelphia suburbs, with active spread in Chester County. At least 11 counties show community transmission, according to the department.

State staff have administered more than 8,300 MMR doses this year, with August the strongest month for uptake, according to department data cited by ABC News (opens in new tab). Nationally, CDC data cited by ABC News (opens in new tab) put U.S. 2026 measles cases above 3,600 across 45 states and D.C.