The Centers for Disease Control and Prevention is stepping up its response in Pennsylvania after two unvaccinated residents of Lancaster County died from measles-associated illness, marking the state’s first measles-related deaths in 35 years. The deaths come as the United States faces its worst measles year in decades, with 2,777 confirmed cases reported nationally through August 20.
The CDC and Department of Health and Human Services said they extend their condolences to the families and communities affected. The agency said it is working closely with state and local health departments to strengthen response efforts, support affected communities and communicate measures that can help slow transmission.
The CDC also reiterated that MMR vaccination remains the most effective protection against measles and said it will continue following Pennsylvania’s lead while providing resources to support the state’s response.
Pennsylvania Records Its First Measles Deaths in 35 Years
The Pennsylvania Department of Health confirmed the two deaths on August 25. Both individuals were unvaccinated residents of Lancaster County, but state officials did not release additional identifying information to protect their privacy.
The deaths are the first measles-associated fatalities reported in Pennsylvania in 35 years, underscoring how dramatically the disease has returned after being largely eliminated in the state for decades.
Pennsylvania has reported 393 measles cases across 28 counties so far in 2026, according to the state health department.
The state has responded by expanding vaccination access in affected communities. Since an outbreak began in April, Pennsylvania has administered more than 4,100 vaccinations through pop-up clinics, while more than 35,000 Pennsylvanians received an MMR vaccine in July alone — about 10,000 more doses than in a typical month.
CDC Data Show the Outbreak Is Much Larger Nationwide
Pennsylvania’s deaths are occurring against a much broader national resurgence.
CDC data updated August 21 show 2,777 confirmed measles cases in the United States in 2026 as of August 20. The total already exceeds the 2,289 cases recorded during all of 2025, which was itself the country’s worst measles year in more than three decades.
The CDC has also recorded 36 outbreaks in 2026. About 94% of confirmed cases — 2,614 of 2,777 — are associated with outbreaks, including outbreaks that began in either 2025 or 2026.
That makes the Pennsylvania deaths more than an isolated state-level development. They are occurring during a sustained national outbreak in which measles is again spreading through communities with gaps in vaccination coverage.
Why Vaccination Coverage Matters
Measles is highly contagious and can spread through the air when an infected person coughs or sneezes. According to the Pennsylvania Department of Health, the virus can remain infectious in the air and on surfaces for up to two hours after an infected person leaves an area.
The CDC says two doses of the MMR vaccine are 97% effective against measles, while one dose is about 93% effective.
But national vaccination coverage has slipped below the level considered necessary to maintain strong community protection. CDC data show that MMR coverage among U.S. kindergartners fell from 95.2% in the 2019–20 school year to 92.4% in 2025–26, leaving an estimated 280,000 kindergartners at risk.
That 95% threshold matters because measles can spread rapidly once the virus enters communities where a larger share of people are not protected.
Lancaster County Is at the Center of the Pennsylvania Outbreak
Lancaster County has been one of the areas most closely associated with Pennsylvania’s 2026 measles outbreak.
The county is also home to one of the country’s largest Amish communities. AP reported that approximately 88% of Lancaster County kindergartners were up to date on measles vaccination during the last school year, below the 95% level generally needed to maintain strong community immunity.
State officials have therefore focused heavily on increasing access to MMR vaccination and providing information to families and healthcare workers.
Pennsylvania’s health department said it has already held 91 measles vaccine pop-up clinics this year and plans another 40 in the weeks ahead.
What the CDC Is Doing Now
The CDC’s response is focused on supporting Pennsylvania rather than taking over the state’s outbreak investigation.
State and local health departments lead measles investigations, while the CDC provides assistance and resources when requested. The agency said it is working with Pennsylvania health authorities to strengthen response operations and help affected communities.
The CDC is also emphasizing vaccination and public communication as officials attempt to prevent additional transmission.
For communities facing exposure, the agency’s message remains straightforward: vaccination is the strongest available protection against measles.
Why These Deaths Are a Warning for the Rest of the US
The Pennsylvania deaths arrive at a critical point in the national measles resurgence.
The United States eliminated endemic measles transmission in 2000, a public-health achievement made possible by high vaccination coverage. But declining coverage, international measles activity and pockets of under-vaccination have created conditions in which imported infections can once again fuel sustained outbreaks.
With the national case count already above last year’s total and 94% of 2026 cases linked to outbreaks, Pennsylvania’s two deaths show the potential consequences when measles spreads through communities with insufficient protection.
The immediate priority for health officials is containing transmission, identifying people who may have been exposed and increasing vaccination coverage in communities where immunity is low.
The CDC says it will continue working with Pennsylvania and local health authorities as the state responds to the outbreak.
