Delaware County has reported zero confirmed measles cases. But health officials there detected the virus in a wastewater sample earlier in the summer of 2026, the Philadelphia Inquirer reported Sept. 19, meaning someone carrying measles used a bathroom connected to the county's public water supply.
That finding takes on new urgency after Pennsylvania recorded its fifth measles-associated death on Wednesday, Sept. 30. The statewide case count has reached 943 across 39 counties, with 176 people hospitalized, the Pennsylvania Department of Health announced.
About 40% of kindergartens in the Philadelphia region failed to meet the 95% MMR (measles, mumps and rubella) vaccination threshold during the 2025-26 school year, up from about a third the year before, according to the Inquirer's analysis of state data. Radnor and Haverford townships fall within that region.
The latest death involved an unvaccinated Lancaster County resident, according to WHYY. It was the third measles-associated death linked to that county in 2026. The health department did not release the person's age or other identifying details, citing privacy protections.
Lancaster County remains the outbreak's epicenter with 381 cases and an 85% vaccination rate, CBS Philadelphia reported. Pennsylvania leads the nation in measles cases this year. The last time the United States recorded more than four measles deaths in a single year was 1991, according to CNN.
Nearly all of the state's infections involve unvaccinated people. Only four confirmed cases, less than 1%, occurred in vaccinated individuals, the health department said. The statewide total includes 40 new cases reported since Monday, Sept. 28.
Dr. Lawrence Livornese, an infectious disease specialist at Main Line Health, told CBS Philadelphia that declining vaccination rates are driving the spread. "It's not the kind of thing you want to be No. 1 in, that's for sure," Livornese said of Pennsylvania's national lead in cases.
The outbreak has driven a sharp increase in MMR vaccinations. Providers typically administer about 25,000 doses per month statewide. In August, they gave more than 49,000. In September, more than 53,000 doses were administered, the health department said. State health staff have also given more than 5,500 vaccinations at 180 pop-up clinics in affected communities since the outbreak began in late April.
Lancaster County Coroner Dr. Stephen Diamantoni told CNN on Sept. 30 that the latest death had not come through his office. He warned that the situation could intensify with colder weather ahead.
The MMR vaccine, given in two doses, provides 97% lifetime protection against measles. Symptoms begin with fever, cough, runny nose and red, watery eyes, followed days later by a rash starting on the head and spreading downward. Symptoms can appear 7 to 21 days after exposure.
Residents who believe they were exposed or are experiencing symptoms can call the state's toll-free hotline at 877-PA-HEALTH (877-724-3258).
