Pennsylvania measles outbreak reaches 1,004 cases across 39 counties, largest in U.S. in three decades

Pennsylvania is battling the largest U.S. measles outbreak in three decades, reaching 1,004 cases across 39 counties and causing five deaths. The outbreak is heavily concentrated in Lancaster County's Amish community, where historical vaccination rates are low due to financial and cultural factors rather than religious objections. Public health efforts are severely challenged by structural gaps, as only seven of Pennsylvania's 67 counties have their own health departments, leaving the epicenter without local infrastructure to combat the highly contagious virus.

Scale of the Pennsylvania outbreak

• ▪The Pennsylvania measles outbreak, which began in late April 2026, surpassed South Carolina's earlier 2026 outbreak of 997 cases to become the nation's largest in 30 years.
• ▪The Pennsylvania Department of Health confirmed that the state's measles outbreak reached 1,004 cases across 39 counties as of October 5, 2026, making it the largest measles outbreak in the United States in three decades.

Hospitalizations and deaths

• ▪The five measles-associated deaths reported by Pennsylvania health officials include a teenager with severe brain inflammation, a 40-year-old unvaccinated woman with asthma, two babies, and an unvaccinated Lancaster County resident.
• ▪Among pediatric measles cases in the Pennsylvania outbreak, 18 percent have required hospitalization, with doctors treating children for severe dehydration, liver infections, secondary bacterial infections, and brain inflammation.
• ▪The Pennsylvania Department of Health reported 198 hospitalizations and five confirmed deaths associated with the measles outbreak as of October 5, 2026.

Spread within the Amish community

• ▪Amish families stated that vaccination is a matter of personal or family preference rather than religious objection, with low uptake often driven by a lack of commercial insurance and the practice of paying for medical care in cash.
• ▪The Amish population in Lancaster County, Pennsylvania, and neighboring counties in Ohio are bearing the brunt of the measles outbreak, with Lancaster County accounting for approximately 40 percent of Pennsylvania's cases.
• ▪Health investigators trace the spread of the measles virus in Pennsylvania and Ohio to exposures at horse auctions in Lancaster, Pennsylvania, and in Bloomfield and Sugarcreek, Ohio, which then spread to weddings, funerals, and church services.

Ohio measles outbreak

• ▪Ohio health officials reported 210 measles cases and 13 hospitalizations as of October 5, 2026, and have shipped approximately 7,100 outbreak-related vaccine doses to providers in 2026.
• ▪In 2026, the highest numbers of Ohio's measles cases were concentrated in Geauga, Wayne, and Ashtabula counties, which recorded 49, 44, and 32 cases respectively.

Surge in MMR vaccinations

• ▪Pennsylvania Department of Health nurses have administered 8,843 MMR vaccine doses in response to the outbreak, including more than 5,700 doses at 192 pop-up clinics in affected communities since late April 2026.
• ▪Statewide MMR vaccine administration by Pennsylvania healthcare providers surged to more than 49,000 doses in August 2026 and over 53,000 doses in September 2026, compared to a typical monthly average of 25,000 doses.

Local public health infrastructure challenges

• ▪Pennsylvania's public health response is hindered because only seven of the state's 67 counties maintain their own local health departments, leaving the majority of counties reliant on finite state-level staff.
• ▪Lancaster County, the epicenter of the Pennsylvania measles outbreak with 381 cases, lacks its own county health department, prompting local doctors and officials to advocate for establishing one to manage the crisis.
• ▪Delaware County Health Department Director Lora Werner noted that local public health efforts are facing challenges following the bankruptcy and collapse of Crozer Health, the county's largest healthcare system and pediatric care provider.

Vaccine skepticism and misinformation

• ▪Public health officials express concern that rising vaccine skepticism in the United States, fueled in part by public statements from Health and Human Services Secretary Robert F. Kennedy Jr., is undermining herd immunity.
• ▪Chester County Health Department Director Jeanne Franklin reported that nurses have encountered residents who believe misinformation about the MMR vaccine, including false claims that the vaccine causes sterility or contains a microchip.

Debatable claims

• ▪Declining the measles vaccine is a legitimate exercise of personal family preference
• ▪Robert F. Kennedy Jr.'s public statements are the main cause of rising U.S. vaccine skepticism