Pennsylvania health officials confirmed two additional measles-associated deaths on Tuesday, bringing the state’s total to four deaths linked to the virus in the past month. The latest fatalities involved an 18-year-old from Mifflin County and a 40-year-old woman from Jefferson County, both of whom were unvaccinated, according to the Pennsylvania Department of Health.
The 18-year-old died from acute disseminated encephalomyelitis, a rare neurological complication of measles, while the 40-year-old had pre-existing conditions including asthma and severe lung disease. These deaths follow two infant fatalities in Lancaster County last month—one a newborn and the other a 6-week-old—both too young to receive the measles, mumps, and rubella (MMR) vaccine. The Pennsylvania health department defines a measles-associated death as one occurring within 30 days of symptoms, supported by clinical evidence, lab tests, and exposure history.
The state’s outbreak has now reached nearly 700 confirmed cases, marking the worst year for measles in the U.S. since 1991. Nationally, seven measles-related deaths have been reported in the last two years, exceeding the combined total from the previous three decades.
Vaccination Status and Public Health Impact
The MMR vaccine, typically administered in two doses (at 1 year and age 5), provides 97% protection against measles. The two infant deaths occurred before eligibility for vaccination, while the adult and teenage victims were unvaccinated. Health officials reiterated that vaccination remains the most effective tool to prevent severe outcomes, including death.
State and Local Response
The Pennsylvania Department of Health has not released additional details about the latest deaths but confirmed they meet the criteria for measles-associated fatalities. The department’s definition includes clinical evidence of infection, positive lab results, and exposure history, alongside medical records verifying measles as a contributing factor.
National Context
The U.S. has recorded seven measles-related deaths in the last two years, compared to just three in 2023. The surge in cases and fatalities has prompted renewed calls for vaccination compliance, particularly in communities with low immunization rates.
Health experts warn that measles is highly contagious, with complications including pneumonia, encephalitis, and death—especially in unvaccinated individuals and young children. The virus can remain airborne for up to two hours after an infected person leaves a room, increasing transmission risks in unvaccinated populations.