Pennsylvania’s measles outbreak has reached 903 confirmed cases as of Monday, September 28, 2026, with 13 new infections reported since Friday. The surge, centered largely in Lancaster County, marks the state’s worst measles resurgence in decades, prompting ongoing concerns about vaccination rates and community transmission across 39 counties.
Pennsylvania Department of Health measles tally
Outbreak Growth and Regional Impact
The Pennsylvania Department of Health reported that the state’s measles tally climbed to 903 infections by Monday, following a steady increase of 68 new cases since the previous Wednesday. Health officials have identified community transmission in at least 11 of the state’s 67 counties, meaning the virus is spreading locally where the specific source of infection remains unknown. Data from the Pennsylvania Department of Health showed that 176 individuals with measles required hospital care, marking a rise from the 164 cases noted on September 23. Lancaster County, with the highest number of cases, remains the hardest-hit area in the state.
Across the state, the Pennsylvania Department of Health confirmed that 176 people have been hospitalized, and four measles-associated deaths have been reported. Two of the deaths were among unvaccinated adults: an 18-year-old and a 40-year-old. Among infants too young to be administered the measles, mumps, rubella (MMR) inoculation, two additional fatalities occurred. Individuals who have received the full course of the MMR vaccination account for fewer than 1% of the state’s total infections—amounting to four cases, as reported by the DOH. State health department figures indicate that adults aged 25 to 49 account for the largest share of infections, with the 18-to-24 age bracket following closely behind. Southeast Pennsylvania’s Lancaster County has logged the state’s peak case count at 363, while Mifflin County situated in the central region follows with 105.
Vaccination Trends and Public Health Guidance
State data indicates that the vast majority of cases involve unvaccinated individuals, with fewer than 1% of the total cases occurring in people who are fully vaccinated. Department of Health records indicate that personnel have distributed in excess of 8,300 MMR immunization shots over the course of the current year. August saw the peak distribution rate with approximately 3,500 vaccine doses handed out, trailed by September during which roughly 2,500 doses were dispensed.
Public health experts continue to warn against visiting clinical settings if an individual suspects they have been infected, as this risks further exposure. If you’ve been exposed, it is important to talk to a healthcare professional, but don’t go into an urgent care or an ER because you may be inevitably spreading it to other vulnerable people,
ABC News medical contributor Dr. Alok Patel told “ABC News Live” on Friday.
Dr. Patel further advised that individuals who have been exposed may need to monitor their health closely. Up to a 21-day period of isolation or meticulous symptom observation may be mandated for exposed persons, given that the measles virus requires this duration to manifest symptoms during which transmission to others can happen inadvertently.
National Context and CDC Monitoring
The situation in Pennsylvania is part of a broader national trend. Across the United States during 2026, a total of 3,659 confirmed measles infections had been documented up to September 24, 2026. Out of this total, 47 different jurisdictions—namely Alabama, Alaska, Arizona, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York City, New York State, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming—accounted for 3,642 of these reported measles cases. A total of 17 measles cases were reported among international visitors to the United States. A total of 40 fresh outbreaks have emerged during 2026, with outbreak-related cases comprising 95% of all confirmed totals (3,478 out of 3,659), which breaks down to 2,094 originating from 2026 outbreaks and 1,384 linked to outbreaks initiated in 2025.
While the CDC has reported one death nationally, it has not specified the location of that fatality. A note on the agency’s website said the number is subject to change.
Federal health officials are currently reviewing how measles-related deaths are classified, a process that has sparked a disagreement between Governor Josh Shapiro and US Health Secretary Robert F. Kennedy Jr. over how many of the fatalities were directly caused by the virus, soon after which the Centers for Disease Control and Prevention said it was reviewing how it classifies measles-related deaths. Meanwhile, nationwide immunization coverage has faced challenges in bouncing back to pre-pandemic levels, with statistical records showing that 92.4% of kindergarten students obtained the MMR inoculation throughout the 2025 to 2026 academic term. This figure falls short of the 95.2% coverage documented prior to the COVID-19 pandemic during the 2019 to 2020 school term.
