Pennsylvania health officials confirmed on August 25 that two unvaccinated residents had died from measles, marking the first measles-related fatalities in the U.S. this year and the first in Pennsylvania in 35 years. One of the deceased was an infant, while the age of the second individual has not been disclosed.
The Pennsylvania Department of Health reported 424 confirmed measles cases across 28 counties as of the latest update, with 94 new cases recorded in the past week. 73 hospitalizations have occurred due to complications from the disease. Health Secretary Debra Bogen stated that the outbreak has spread almost entirely among the unvaccinated, noting that two doses of the MMR vaccine are 97% effective.
Lancaster County, where both deaths occurred, has seen a decline in childhood vaccination rates, dropping from 95.5% in 2017 to 87.6% in 2025. The state’s case data indicates that adults aged 18–49 account for 63% of all cases, while children under 18 represent 31%. The outbreak has accelerated despite schools not yet fully reopening, with 212 cases reported between August 1 and August 24.
Officials emphasized the vulnerability of infants aged 6–11 months, who lack full immunity from maternal antibodies and have not yet received their first MMR dose. Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, noted that some health authorities recommend an early MMR dose for infants at 6 months in high-risk areas. This was the case during a 2023 Texas outbreak, where two unvaccinated girls died from measles.
Nationally, the U.S. has recorded 2,777 measles cases this year, the highest total in 35 years. Measles was declared eliminated in the U.S. in 2000, but the Pan American Health Organization is set to review whether the country has lost its elimination status in November 2025.