Since Wednesday, September 9, Pensylvania state health officials report an additional 52 measles cases, bringing the total to 676 confirmed cases in 2026.
This leapfrogs Pennsylvania over South Carolina (671) as the US state reporting the most measles cases this year.
37 counties have been affected by measles with Lancaster County reporting the most (295), followed by Mifflin (74) and Chester (65) counties.
If Lancaster County was a state, it would have the fourth most measles of any state in the country.
To put in perspective, in 2025, Pennsylvania reported 16 cases in over the whole year.
To date, 124 cases required hospitalization and two measles-associated deaths have been recorded.
The Pennsylvania Department of Health (DOH) identified four individuals, three adults and one child, with measles who were all appropriately vaccinated for their given ages. The individuals are residents of Centre, Jefferson, Lancaster, and Lycoming counties. None of these individuals were hospitalized.
These four cases represent less than one percent of total confirmed cases in Pennsylvania. According to the national CDC dashboard, approximately 3 percent of measles cases across the country in 2026 have occurred in fully vaccinated individuals.
The presence of so few cases among vaccinated individuals in Pennsylvania out of the more than 670 total cases confirms what decades of clinical evidence show: two doses of the MMR vaccine remain the single best protection against measles.
People who are vaccinated and become infected with measles experience milder symptoms and are less likely to have complications or be hospitalized.
The MMR vaccine is still the best protection against the measles virus because it builds the level of community immunity that virtually eliminated measles in the U.S. for a quarter of a century.
If you like the reporting on Outbreak News Today, please consider a paid subscription for $5/month or $30 a year. Help support the cause of this niche journalism. It is appreciated.