Pennsylvania has become the hardest-hit state in a nationwide measles resurgence, with at least 1,338 confirmed cases across 44 counties so far this year, state health officials said Friday, Oct. 23. The outbreak is part of a broader rise: U.S. Centers for Disease Control and Prevention data showed more than 4,580 cases nationwide as of Oct. 22—more than twice the total for all of 2025. The CDC said 96% of people who contracted measles in 2026 were unvaccinated or had an unknown vaccination status. Pennsylvania reported 21 new cases as of Oct. 21. More than 250 people have been hospitalized and five have died, according to the state Department of Health. Three of the deaths were among Lancaster County residents. Lancaster and Mifflin counties, among the areas with the most cases, have seen outbreaks affecting local Amish communities, where vaccination rates are low. On Thursday, state Health Secretary Dr. Debra Bogen met with Mifflin County health care providers to discuss local needs and the response. “Listening to the people on the ground caring for people in affected communities like Mifflin County is essential to refining our public health response,” Bogen said in a statement. The state says demand for measles shots has climbed. More than 39,000 measles vaccines were administered in Pennsylvania during the first three weeks of October, compared with an average of about 25,000 in a full month, the health department said. Health officials recommend vaccination as the strongest protection. The CDC says two doses of the measles, mumps and rubella vaccine are nearly 97% effective against measles; one dose is about 93% effective. Other states are also confronting outbreaks. New York had more than 160 confirmed cases as of Oct. 20 after Gov. Kathy Hochul declared a disaster emergency earlier this month. Utah had more than 700 cases this year, though its health department reported no diagnoses in the three weeks before Oct. 20. South Carolina recorded at least 997 cases in 2026; that outbreak ended in April.