Vaccinated PA Residents Contract Measles as Outbreak Surges

Four Pennsylvanians fully vaccinated with two MMR doses have fallen ill with measles in a statewide outbreak that has reached 676 cases, including 295 in Lancaster County; three are adults and one is a child, and none were hospitalized. Health officials note that while breakthrough infections are rare, they can occur as transmission rises. The measles vaccine remains about 97% effective after two doses, and doctors say illness tends to be milder in those who are vaccinated. The outbreak has spurred continued emphasis on vaccination and public health monitoring.