Pennsylvania health officials confirmed two additional measles-associated deaths this week, bringing the state’s total to four this year and marking a grim new milestone in what Governor Josh Shapiro has called the state’s worst measles outbreak in more than three decades. The two latest deaths occurred in Jefferson and Mifflin counties, following two earlier deaths among infants in Lancaster County reported in August, the state’s first measles-related fatalities in 35 years.
Who Died and What Health Officials Know
The Pennsylvania Department of Health said the Jefferson County resident was a 40-year-old woman with asthma and severe lung disease who died over the weekend. The Mifflin County resident was 18 years old, according to the county coroner’s office. Both individuals were unvaccinated against measles. The department said the two deaths were confirmed as measles-associated only after rigorous investigations involving the respective county coroners’ offices.
Those two deaths follow the state’s first measles fatalities in over three decades, confirmed in August: a newborn who died shortly after birth and a six-week-old infant, both residents of Lancaster County. Investigators said the infant’s death involved a laceration of the spleen that may have resulted from a measles infection contracted by the mother.
A Rapidly Growing Outbreak
Pennsylvania has now reported nearly 700 measles cases across 38 of its 67 counties in 2026, with 133 people hospitalized, according to the state health department. Most cases have been concentrated in Lancaster County. Officials say fewer than one percent of the confirmed cases occurred in people who were fully vaccinated, though the department has also identified four vaccinated individuals, residents of Centre, Jefferson, Lancaster, and Lycoming counties, who contracted the virus despite vaccination, a reminder that no vaccine offers absolute protection even as it dramatically reduces risk.
How Pennsylvania Defines a “Measles-Associated” Death
The state health department applies a specific clinical standard when classifying a death as measles-associated: the person must have clinical evidence of measles infection and a positive laboratory test, and the death must occur within 30 days of symptom onset and not be attributable to unrelated causes, such as an accident. Investigators also weigh additional factors, including documented exposure to measles before death and supporting medical records. To protect patient privacy, the department has not released further identifying details about the individuals who died.
A Dispute Over How Deaths Are Counted Nationally
The Pennsylvania deaths have become entangled in a broader, contentious disagreement over how measles fatalities are counted at the federal level. Governor Shapiro has criticized federal Health and Human Services Secretary Robert F. Kennedy Jr., accusing him of politicizing the state’s measles deaths by publicly disputing whether the earlier Lancaster County deaths were directly caused by measles before the underlying causes had been formally established.
“CDC is applying a consistent national standard rather than allowing politicians to decide which deaths appear in federal mortality statistics.”
— Robert F. Kennedy Jr., U.S. Secretary of Health and Human Services
That dispute reflects a real distinction between two separate counting standards: Pennsylvania’s broader “measles-associated” classification, used for state public health response purposes, and the CDC’s more narrowly defined “measles-caused” classification for national mortality statistics, which typically lags behind state-level reporting as federal reviewers complete their own verification process. Nationally, health officials have said recorded measles-linked deaths since 2025 have already surpassed the total recorded over the prior two decades combined, even as the exact tally attributed to the CDC’s stricter standard remains lower than the count reported by Pennsylvania alone.
Why Vaccination Rates Matter Here
Public health officials continue to point to the MMR vaccine as the clearest lever available to curb the outbreak. One dose is roughly 93 percent effective against measles infection, and the full two-dose series is about 97 percent effective, according to CDC data. Kindergarten MMR vaccination coverage has declined for three consecutive school years nationally, falling to 92.4 percent in the 2025-2026 school year from 95.2 percent before the COVID-19 pandemic, a gap public health officials say leaves growing pockets of communities vulnerable to outbreaks like Pennsylvania’s.
Pennsylvania Secretary of Health Dr. Debra Bogen has repeatedly urged residents to get vaccinated, noting that measles was largely eliminated in the state for more than three decades, leaving many residents unfamiliar with a disease that can, in rare cases, prove fatal.
“My thoughts are with the two families who lost loved ones to this highly contagious virus.”
— Dr. Debra Bogen, Pennsylvania Secretary of Health
What Comes Next
Pennsylvania’s Department of Health has said it remains committed to working with local partners to contain the outbreak and prevent further deaths, primarily by expanding access to MMR vaccination and public information about the disease. With cases now spread across more than half the state’s counties and hospitalizations climbing, health officials say the coming weeks will test whether public health messaging, contact tracing, and expanded vaccine access can outpace a virus that spreads efficiently through communities with gaps in immunization coverage, even as the broader political dispute over how these deaths are counted and reported continues to play out at the federal level.