Pennsylvania’s reported measles-associated death toll has reached four in an outbreak that had grown to 693 confirmed cases across 38 counties as of Sept. 14, according to reports by CNN, FOX 29 Philadelphia and the Associated Press citing state health officials. The newest reported death involved an unvaccinated 18-year-old in Mifflin County.
The update follows the Pennsylvania Department of Health’s announcement of two measles-associated deaths among unvaccinated Lancaster County residents, which it described as the state’s first measles-related deaths in 35 years. CNN, FOX 29 Philadelphia and the Associated Press later reported that the statewide total had risen to four.
What is known about the four deaths
Reporting published Sept. 15 and 16 identified the additional deaths as involving residents of Jefferson and Mifflin counties. Pennsylvania officials have described all four deaths as measles-associated, and reports said all four people were unvaccinated.
The Mifflin County death has a more specific reported finding. The county coroner determined that the 18-year-old died of acute disseminated encephalomyelitis, or ADEM, and characterized the death as natural and linked to measles, according to Medical Daily’s account of the coroner’s release. The available reporting does not include the teen’s medical records or further clinical history.
Why state and federal death counts can differ
Pennsylvania’s phrase “measles-associated death” has a defined public-health meaning. Under the state health department’s measles guidance, a death must have clinical evidence and a positive laboratory test for measles, occur within 30 days of symptom onset, and not be due to an unrelated cause. The classification does not require measles to be designated as the sole underlying cause on a death certificate.
CNN reported that the Centers for Disease Control and Prevention had sought more information about whether measles caused or contributed to the initially reported Pennsylvania deaths. Medical Daily reported that the National Center for Health Statistics had no 2026 death records listing measles as the underlying cause.
The state surveillance category and underlying-cause death coding address related but different questions. Pennsylvania can classify a death as measles-associated under its laboratory, timing and exclusion criteria, while a federal mortality record relies on the underlying cause certified and coded on a death certificate.
The distinction is material for the first two deaths. Pennsylvania classified both Lancaster County deaths as measles-associated. CNN reported that a county coroner said measles caused the death of one six-week-old infant, while a ruptured spleen was not caused by measles in the other newborn’s death. It would therefore be inaccurate to say measles was established as the sole cause of every death in the four-person tally.
Outbreak snapshot and prevention
The reported total of 693 confirmed cases in 38 counties reflects the state’s Sept. 14 outbreak update, as reported by CNN and FOX 29 Philadelphia. Outbreak totals are dated snapshots that can change as investigations identify, confirm or reclassify cases.
Pennsylvania health officials say measles can remain infectious in the air and on surfaces for up to two hours after an infected person has left an area. The state says the disease can cause complications including pneumonia and brain swelling, with young children among those at higher risk of severe illness.
Vaccination remains the principal protection measure. The state says two doses of measles, mumps and rubella vaccine provide about 97% protection against measles.
Four deaths among 693 reported cases is not a reliable estimate of a fixed measles fatality rate for Pennsylvania. The case count is preliminary, infections can go unrecognized, and public clinical details about the deaths remain limited. Pennsylvania has reported four measles-associated deaths; the Mifflin County coroner’s reported finding is a separate individual cause-of-death determination.