Lancaster County has recorded 80 measles cases this year—by far the most in Pennsylvania, which has reported 132 cases statewide.
None of the 132 infected people were fully vaccinated, and health officials tied the outbreak to under-vaccinated communities where hesitancy, access issues and ideological objections persist.
Lancaster County's two-dose MMR rate for kindergarteners was nearly 88.5% in the 2024-25 school year, below the level experts generally view as protective against measles spread.
More than 750 MMR shots have already been given at Lancaster-area pop-up clinics, with additional clinics planned as officials try to contain the outbreak.