Prepared to meet the new measles moment

Measles is the most contagious virus on earth. It can linger in a room for two hours after an infected person leaves the area, infecting up to 90 percent of unvaccinated or medically vulnerable people exposed. And as of early September, it had sickened at least 577 people in Pennsylvania, with nearly 250 cases in Lancaster County.

With vaccine-preventable illnesses like measles re-emerging close to home, Penn Medicine is prepared—and committed to keeping patients, staff, and communities as healthy and safe as possible.

Measles in the spotlight

In 2025, 2,289 cases of measles were confirmed in the United States, mostly among unvaccinated children. As of early September 2026, the number of cases had surpassed 2,900 and continues to rise.

“We’re on pace to potentially double the number of cases that we had last year,” said Judith O’Donnell, MD, chief medical officer (CMO) & chief of Infectious Diseases, Penn Presbyterian Medical Center and associate CMO for Health Care Epidemiology for the University of Pennsylvania Health System (UPHS).

To stop the spread of measles, 95 percent of a population must be immune, and the measles, mumps, and rubella (MMR) vaccine is the safest, most effective way to prevent measles. But throughout pockets of the United States, a decrease in vaccinations has caused this rate to fall short, substantially increasing the risk of outbreaks.

And it’s not just people who have decided against vaccination for themselves and their families who are at risk. Infants, pregnant people, and individuals whose immunity is weakened by illness or treatments such as chemotherapy, can suffer severe illness or even death.

What’s most shocking to many health experts isn’t just that cases are at a 35-year high, but that measles had been declared eliminated in the United States in 2000—meaning that public health efforts had successfully wiped it out as a continuously circulating virus. Penn Medicine is addressing this resurgence on multiple fronts.

A coordinated approach

As measles hits home locally, Jeffrey Martin, MD, chair of Family and Community Medicine at Penn Medicine Lancaster General Health, said protecting patients, visitors, and staff from exposure is key across inpatient and outpatient settings.

“Our teams are reinforcing early identification and screening protocols, promptly isolating patients with suspected symptoms, and following established infection prevention procedures,” he explained.

Signs posted outside hospitals and some outpatient offices ask those who are unvaccinated or not immune, and have measles symptoms, to call for guidance before entering the facility. Other tactics: offering accelerated vaccination schedules to protect infants, hosting free vaccine clinics, promoting telehealth visits, and testing patients in their cars.

Martin and his teams in Lancaster are also working closely with public health partners, including the Pennsylvania Department of Health (DOH), and evaluating additional measures as the situation evolves—such as reviewing NICU, Pediatric, and Oncology floor visitation restrictions and enhancing room cleaning protocols, as well as exploring the use of alternative entrances for sick visits in their urgent care and outpatient clinics.

Though measles outbreaks are notably higher in Lancaster County, safety precautions are taken seriously at all Penn Medicine facilities.

“We're always really concerned about our transplant patients, advanced HIV patients, and cancer patients who are on chemotherapy or who just had a CAR T cell therapy or a stem cell transplant,” O’Donnell said.

She explained that Penn has infectious disease doctors who care exclusively for transplant patients—guiding them before and after their transplants and monitoring their antibody levels, since they must take immunosuppression drugs that increase their susceptibility to vaccine-preventable infections.

It’s not only measles that Penn Medicine is addressing proactively. As the world was reminded during the COVID-19 pandemic, infectious disease outbreaks and major disasters can quickly overwhelm a health system—which is why preparedness remains a leading priority.

The epidemiology and infectious disease teams that led Penn Medicine’s robust pandemic response rely on data from their “outstanding public health partners,” at the Departments of Health for the City of Philadelphia, Pennsylvania, and New Jersey to keep apprised of potentially communicable diseases as they arise, O’Donnell explained.

Penn Medicine’s emergency departments (EDs), Special Treatment Unit, and Hospital Emergency Response Team habitually train to respond to a variety of infectious diseases and risk profiles. Protocols for everything from proper donning and doffing of personal protective equipment (PPE) to cleaning patient rooms are routinely reviewed with nurses, housekeeping staff, and other employees.

All of this experience came together when the system began prepping, years in advance, for the influx of visitors traveling to Philadelphia in the summer of 2026 for the FIFA World Cup, America’s 250-year festivities, and Major League Baseball’s All-Star Week. Jack Welsh BSN, RN, CEN, an emergency preparedness specialist at the Hospital of the University of Pennsylvania, said, “We worked at our four downtown facilities, with a focus on mass casualty [exercises], hazmat events, and preparing our command center leadership to manage the hospitals during an event.” In addition to acute medical issues, Penn Medicine’s downtown EDs had to screen and be ready for patients with a wide range of potential pathogen exposures from their countries of origin.

The effort, O’Donnell said, was “truly multidisciplinary.” Staff training on infection control spanned frontline ED providers, trauma and surgical teams, patient safety officers, directors of environmental safety, the hospital emergency response team, and more. O’Donnell’s team added intranet resources that physicians could access if they had questions, and partnered closely with the Philadelphia DOH, which enhanced its surveillance of conditions that might show up in the ED.

Communication: A powerful tool

There are many reasons illnesses like measles are returning—including pandemic-related disruptions to routine immunization schedules, and vaccine hesitancy fueled by mistrust in public health institutions and the spread of misinformation on social media.

Another factor, ironically, is the effectiveness of childhood vaccines. As Martin pointed out, “They’ve done such a good job … that people ask, ‘Why do I need this?’”

Because today’s parents grew up without experiencing measles, polio, whooping cough, and other highly contagious diseases, Penn Medicine is focused on “getting people to truly understand the devastating outcomes that are prevented by these vaccines,” O’Donnell said. “We've lost all of that collective historical memory.”

For example, in some cases parents may opt against the MMR vaccine, figuring their child would gain immunity to measles if they caught the disease. While that’s true, they may be unaware of other risks with measles infections, from “immune amnesia” that erases the child’s existing immunity to other viruses and bacteria, to rare but serious and permanent injuries, or even a fatal brain disorder that can strike years later.

To fill that gap, Pia Fenimore, MD, vice chair of pediatrics at Penn Medicine Lancaster General Hospital, and Joan Thode, MD, a pediatrician with Lancaster General Health’s Roseville Pediatrics, together wrote an op-ed series for their local newspaper explaining, in uncomplicated language, how vaccine-preventable illnesses affect children. The articles aimed to help parents make informed choices based on science, not speculation. Providers also reviewed the articles with families during office visits.

Thode and Fenimore noted as one measure of success that patients have brought printed copies of the articles to discuss at appointments. And in the newborn nursery at Penn Medicine Lancaster General Health’s Women & Babies Hospital, the hepatitis B article has been especially effective. After reading and discussing it, approximately 50 percent of initially hesitant families chose to proceed with the birth-dose vaccine.

But it’s not just patients, families, and community members that Penn Medicine is educating. The UPHS Council on Infectious Diseases and Immunization Practices is keeping providers well-informed through an intranet site with information on symptoms, resources to help combat misinformation, and science-backed guidelines for a range of adult and pediatric vaccines. It also leverages Penn’s close relationship with Children’s Hospital of Philadelphia (CHOP), directing providers to CHOP’s richly informative Vaccine Education Center website to support discussions with families who may be vaccine-hesitant or question immunization schedules.

Discussions between patients and clinicians may actually be the most potent tool for reversing the re-emergence of vaccine-preventable diseases.

“Where people get their information from now is very different than it was five or 10 years ago,” O’Donnell said.

While a one-on-one conversation won’t have the same reach as a TikTok post, recent research has shown that a trusting relationship between a health care provider and patient (or family member) has the most impact on the choice to vaccinate.

Prompted by new reminders and screening questions in the electronic health record, Penn Medicine providers are initiating conversations to nurture that trust so that patients will turn to them for guidance, rather than AI or social media.

“I think the key is to ask people, What have you heard? and Is it okay if I ask you what concerns you have about vaccination?” Martin said. “Then I usually ask, Do you mind if I share some information with you that I know about it?”