The measles outbreak in Pennsylvania has become one of the largest in the country in 2026, and it’s still growing. As of the Pennsylvania Department of Health’s most recent statewide update, 624 confirmed cases have been reported across 37 counties, and the state has now recorded its first measles deaths in 35 years.
This article covers where the outbreak stands right now, what’s driving it, the two confirmed deaths in Lancaster County, and what residents should know about symptoms, exposure, and vaccination.
Note: Case counts change frequently as new data comes in. For the most current figures, check the Pennsylvania Department of Health’s live dashboard directly.
Current Measles Outbreak Numbers in Pennsylvania
According to the Pennsylvania Department of Health, the outbreak has climbed steadily since it began in late April 2026:
- 460 confirmed cases across 31 counties in an earlier summer update
- 497 cases across 34 counties shortly after
- 540 cases across 36 counties by late August
- 577 cases across 37 counties in a following update
- 624 confirmed cases across 37 counties in the most recent statewide report
Pennsylvania has reportedly surpassed South Carolina to lead the nation in measles cases for 2026, and some physicians believe the true number of infections is likely higher than what’s officially confirmed, since not every case gets reported or lab-tested.
Nationally, the CDC reported more than 2,900 confirmed measles cases as of late August 2026, already surpassing the 2,289 cases recorded for all of 2025, and marking the highest annual U.S. total since measles was declared eliminated in 2000.
Lancaster County and the First Deaths in 35 Years
Lancaster County has been the epicenter of the Pennsylvania outbreak, accounting for roughly 185 cases on its own, making it one of the largest single-county measles outbreaks in the country this year.
In late August 2026, Pennsylvania health officials confirmed two measles-related deaths, both unvaccinated residents of Lancaster County. These mark the state’s first measles deaths in 35 years and the first measles-related deaths reported anywhere in the U.S. in 2026. Officials withheld further identifying details out of respect for the individuals and their families.
Public health leaders described the deaths as a stark and preventable loss. Given that a safe, effective vaccine against measles has been widely available since the 1970s, health officials have emphasized just how avoidable these outcomes were.
Why Is This Measles Outbreak Happening?
Health officials point to declining childhood vaccination rates as the primary driver behind this year’s outbreaks nationwide, not just in Pennsylvania. National kindergarten MMR vaccination coverage has dropped from about 95.2% in the 2019–2020 school year down to roughly 92.4% in 2025–2026.
That gap matters more than it might seem. Public health experts generally consider 95% vaccination coverage the threshold needed for community, or “herd,” immunity to reliably prevent measles from spreading. Falling below that threshold leaves an estimated 280,000 kindergartners nationwide without documented protection, creating the conditions for outbreaks like this one to take hold and spread through under-vaccinated communities.
Measles Symptoms to Watch For
Measles typically develops in stages, and recognizing early symptoms matters for limiting further spread.
- Fever, often high
- Cough, runny nose, and red, watery eyes
- A rash that typically starts on the head and spreads downward over the following days
- Symptoms generally appear 7 to 21 days after exposure
Measles is highly contagious. The virus can remain infectious in the air and on surfaces for up to two hours after an infected person has left the area, which is part of why it spreads so efficiently in under-vaccinated communities.
How Pennsylvania Is Responding
The Department of Health has ramped up its outbreak response significantly throughout 2026:
- More than 100 pop-up vaccination clinics have been held in affected communities since the outbreak began
- Over 3,900 MMR vaccinations were administered through these pop-up clinics alone
- Statewide, health centers have administered more than 5,700 MMR doses in 2026
- Vaccination interest has surged broadly: Pennsylvania providers typically administer around 25,000 MMR doses per month statewide, but in August 2026 alone, more than 46,000 doses were given
The Department continues to monitor case counts, hospitalizations, and community transmission through its public dashboard, and additional vaccine clinics are being scheduled in response to community need.
What Residents Should Do
Health officials consistently point to the same core guidance for anyone in an affected area:
- Check your vaccination status. The MMR vaccine is given in a two-dose series and is about 97% effective at preventing measles after both doses.
- Get vaccinated if you haven’t already. MMR vaccine is available through health care providers, county or municipal health departments, State Health Centers, Federally Qualified Health Centers, and the Vaccines for Children program.
- Watch for symptoms if you’ve been in an affected county, especially fever, cough, and the characteristic rash, and contact a health care provider before showing up in person if you suspect exposure, to avoid exposing others in a waiting room.
- Stay home if you’re sick, since measles spreads easily through the air and on surfaces.
The overall risk of contracting measles remains low for people who are fully vaccinated, and health officials continue to stress vaccination as the most effective way to protect both individuals and the broader community.
Frequently Asked Questions
How many measles cases does Pennsylvania have in 2026? As of the most recent statewide update, Pennsylvania has confirmed 624 measles cases across 37 counties, with Lancaster County accounting for the largest share.
Has anyone died from measles in Pennsylvania in 2026? Yes. Two unvaccinated residents of Lancaster County died from measles-associated illness, confirmed in late August 2026, marking the state’s first measles deaths in 35 years.
Is Pennsylvania’s measles outbreak the worst in the U.S. right now? Pennsylvania has reportedly surpassed South Carolina to lead the nation in confirmed measles cases for 2026.
How effective is the MMR vaccine against measles? The MMR vaccine is approximately 97% effective at preventing measles after the full two-dose series.
What county in Pennsylvania has the most measles cases? Lancaster County has been the center of the outbreak, with roughly 185 confirmed cases, making it one of the largest single-county outbreaks in the country in 2026.
Why is measles spreading again after being eliminated in the U.S.? Declining childhood MMR vaccination rates, now below the 95% threshold needed for community immunity, have left hundreds of thousands of children without documented protection, creating conditions for outbreaks to spread.
Where can I get an MMR vaccine in Pennsylvania? MMR vaccines are available through health care providers, county and municipal health departments, State Health Centers, Federally Qualified Health Centers, and the Vaccines for Children program.
Conclusion
The measles outbreak in Pennsylvania has grown into one of the largest in the country in 2026, with case counts still climbing and two confirmed deaths in Lancaster County underscoring how serious this preventable disease can become. The core guidance from health officials hasn’t changed: check your MMR vaccination status, get vaccinated if you haven’t, and watch for symptoms if you’ve spent time in an affected area.
For the most current case counts and vaccination clinic locations, check the Pennsylvania Department of Health’s measles dashboard directly, since numbers are updated regularly as the outbreak continues to evolve.