Main Street in central Pennsylvania bustles with cars, horse and buggy carriages, vendors and visitors on the weekly Sale Day. Yet less than a mile away, the Central Pennsylvania Clinic is confronting a measles outbreak that has brought severe illness, hospitalizations and fear to the families it serves.

The clinic’s locked front door displays a photo and description of measles alongside instructions to ring the doorbell. When Dr. Katherine Mascia answers, she greets visitors with a smile and an immediate question: “Any measles symptoms today?”

More than 1,000 cases have been reported by the Pennsylvania Department of Health since the outbreak began in April. It has surpassed recent outbreaks in Texas and South Carolina to become the worst in the United States since the early 1990s, with five deaths reported during the outbreak.

Mifflin County, where the clinic is located, is among the hardest hit areas near the epicenter in Lancaster County. The nonprofit treats children and adults with genetic disorders that are especially common among Amish people and the broader Plain community, where vaccination rates tend to be lower than average.

Mascia said the clinic has experienced an extraordinary concentration of hospital admissions within only a few weeks. Leaders from the federal and state governments, meanwhile, have clashed over the response, including the definition of a measles death and how information about deaths should be released.

The clinic has relied on relationships built through years of patience and persistence. After Pennsylvania reported a measles associated death involving a patient aged 18 in Mifflin County, Mascia said calls poured in from patients and other community members seeking a clear explanation of what happened.

Mascia contacted the county coroner for a formal statement about the cause of death and uses it when responding to questions. She said accurate information and consistent messaging are essential to keeping communication open with the community.

The clinic began preparing for a possible local outbreak after the West Texas outbreak started in January 2025. Its offices lack advanced ventilation systems and negative pressure rooms, meaning that one infected visitor could compromise the entire building for two hours, Mascia said.

Pennsylvania requires a throat swab, blood sample and urine sample to confirm measles. Because testing inside the clinic could create risks, the rear entrance and parking lot have become a makeshift triage area where cars and buggies can spread out and patients can provide samples in a small storage barn.

Mascia said logistical planning matters, but increasing vaccination remains the most important protection. The clinic consistently recommends vaccination without coercion because patients who feel forced may disengage from health care entirely, a particularly dangerous outcome for people managing complex conditions.

“We share that it’s our strong recommendation that everyone be fully vaccinated,” Mascia said. “And if they’re not interested, we repeat our recommendation and say ‘we’re here to help if and when you change your mind.’”

The clinic schedules two hours for new patient visits and one hour for later appointments, giving families time to ask questions. Its main examination room is large enough for entire families, which average seven children, allowing conversations about decisions that may affect every family member.

After the federal Vaccines for Children program stopped providing MMR shots to the clinic because of low demand, Mascia worried that cost would block interested families. Pennsylvania later helped keep the clinic’s pharmacy supplied, just as requests for vaccination began increasing during the outbreak.

The state health department has held nearly 200 vaccination events and administered thousands of MMR doses since spring. At events hosted by the trusted clinic, more than two dozen people were vaccinated in mid August and another 73 in mid September, with interest rising after the Mifflin County death was reported.

Clinic workers also administer vaccines during home visits, sometimes coordinating the timing and location to avoid attention from neighbors. Dr. Helge Hartung said one family avoided church for more than a month to protect a vulnerable infant, then requested an early vaccination as soon as the baby turned 6 months.

The outbreak has also disrupted routine care, fundraising and family finances. Mascia has seen more missed appointments, while executive director Louise Yoder said recent community auctions brought in less support partly because people were sick and avoiding gatherings.

Mascia said numerous hospital stays and ICU admissions have raised concerns about the financial toll on Plain families, many of whom do not enroll in formal health insurance plans. She described the suffering as heartbreaking because measles is preventable and some seriously ill patients waited too long before calling the clinic.