Pennsylvania reported 55 new measles cases, raising the statewide total to 890 across 39 counties, with 173 hospitalizations and four deaths. Fewer than 1% of cases occurred in fully vaccinated people. Lancaster County (359 cases) and Mifflin County (102) remain hotspots. State health officials have administered thousands of MMR doses via pop-up clinics as demand surges, while national measles cases in 2026 exceed 3,600. Health experts urge adherence to CDC two-dose MMR guidance.
Pennsylvania Measles Outbreak Grows to 890 Cases After 55 New Infections; 4 Deaths Reported
Patrick T. Fallon/AFP via Getty Images, FILE - PHOTO: In this Oct. 24, 2025, file photo, a vial of the Measles, Mumps, and Rubella (MMR) vaccination for children is displayed during an immunization event in Los Angeles.
Pennsylvania's measles outbreak expanded with 55 additional confirmed cases since Wednesday, the state Department of Health (DOH) reported, bringing the statewide total to 890 cases across 39 counties. At least 173 people have been hospitalized and four measles-associated deaths have been recorded so far in 2026.
Outbreak Snapshot
DOH data show that fewer than 1% of reported infections — four cases in total — occurred in people who were fully vaccinated with the measles, mumps, rubella (MMR) vaccine. The largest share of cases has been observed in adults aged 25 to 49, followed by those aged 18 to 24.
By county, Lancaster County in southeastern Pennsylvania has reported the most cases (359), followed by central Pennsylvania's Mifflin County with 102 confirmed infections.
Vaccination Response and Demand
Since the outbreak began in late April, state health officials say they have administered more than 5,300 MMR vaccinations at 165 pop-up clinics in affected communities. Overall, state health center staff have provided more than 7,900 MMR doses to residents across the Commonwealth in 2026.
The DOH reported a sharp rise in vaccine demand: typically about 25,000 MMR doses are given each month in Pennsylvania, but more than 49,000 doses were administered in August 2026 and over 38,000 doses during the first three weeks of September.
National Context
Nationally, measles cases have surpassed 3,600 so far in 2026, with infections reported in 45 states and Washington, D.C., according to the Centers for Disease Control and Prevention (CDC).
Expert Comment
"Measles is a nasty virus and highly, highly contagious — the most contagious virus we know — and it's so sad that it continues to occur and afflict even a single child in the United States because it's a completely preventable disease," said Dr. William Schaffner, professor of preventive medicine at Vanderbilt University Medical Center.
What You Should Know And Do
The CDC recommends two doses of the MMR vaccine: the first between 12 and 15 months of age and the second between 4 and 6 years. One dose is about 93% effective and two doses are about 97% effective at preventing measles.
Vaccination coverage has dipped in recent years: in the 2025–2026 school year, 92.4% of kindergartners received the MMR vaccine, down from 95.2% in 2019–2020. Health officials warn that lower coverage increases the risk of further outbreaks.
If you believe you were exposed to measles and are experiencing symptoms, contact your health care provider promptly or call the DOH toll-free hotline at 877-PA-HEALTH (877-724-3258).
Help us improve.
