A visitor later confirmed to have measles was at Children's Hospital of Philadelphia on Sept. 11, prompting city health officials to warn of a probable exposure that included a neonatal intensive care unit. The Philadelphia Department of Public Health said the exposure window ran from 9:30 a.m. to 4:15 p.m. in NICU West, its family lounge, and the hospital atrium, and from 12:05 p.m. to 2:45 p.m. in the main cafeteria. CHOP and state and city health officials are working to give potentially exposed infants a preventive antibody product.
The alert arrives as the outbreak keeps growing. The Pennsylvania Department of Health reported 767 confirmed cases across 38 counties on Sept. 18, including 36 new cases since Sept. 16, along with 150 hospitalizations and four measles-associated deaths.
For parents of medically fragile children, the CHOP exposure makes a hard truth plain: the places these children depend on most, including hospitals and classrooms, are only as safe as the community around them. Babies under 12 months, some children with weakened immune systems, and others who cannot be fully protected by vaccines rely on the people around them being immune.
A NICU Exposure and Antibody Treatment for Infants
Officials have not said how many people were exposed or whether any new cases have resulted. CHOP took immediate action to identify babies who might have been exposed, placed exposed patients in isolation, and is monitoring them for symptoms, Julia Sammons, vice president and associate chief medical officer of the hospital's Office of Preparedness, Prevention and Response, told The Philadelphia Inquirer.
Health Commissioner Dr. Palak Raval-Nelson said the exposure does not pose a broad risk to the city because most residents are vaccinated. Getting vaccinated, she said, is "about protecting our most vulnerable Philadelphians."
Anyone at CHOP during those hours who is not immune and develops measles-like symptoms through Oct. 2 should contact a doctor right away, the city said. Non-immune people who were exposed are asked to wear a mask in indoor public spaces and around unvaccinated people for three weeks after the exposure, because measles can spread for four days before a rash appears.
MedicalDaily previously reported that national measles cases reached 3,471 as Pennsylvania climbed to 767. The CHOP notice changes the practical picture by placing an exposure inside a unit built to protect newborns.
Families of Fragile Children Weigh School, Care, and Everyday Risk
Maggie Gladson of New Oxford, Pennsylvania, near the outbreak's center, told CIDRAP News that her 14-year-old son, Charlie, has Cornelia de Lange syndrome and hypoplastic left heart syndrome. Viral infections have repeatedly sent him to the hospital, and he has needed resuscitation. He is up to date on vaccines, yet she remains uncertain. "We don't know if his measles immunizations are still effective," she said.
The family chose to keep Charlie in school because the routine helps him thrive. Another family profiled by CIDRAP decided to homeschool their daughter as measles outbreaks became more common.
Nearly one-third of Pennsylvania's cases this year involve children under 18, and two of the measles-associated deaths were infants, the Inquirer reported. Nationally, 92.4% of kindergartners received MMR for the 2025-26 school year, below the 95% level needed for herd immunity, CIDRAP noted, citing CDC data.
Children at greatest risk include infants under 12 months and children with weakened immune systems from cancer treatment, transplants, or certain medications. Kids with serious heart, lung, or neurologic conditions who tend to get sicker from common viruses also need extra caution, as do pregnant people who are not immune.
Protection Steps from Pediatric Specialists and Health Officials
Dr. Sarah Long, a Drexel pediatrics professor and pediatric infectious disease physician, told the Inquirer that immunoglobulin, a treatment made from donated adult plasma, can boost an exposed baby's antibodies against measles. Under longstanding CDC measles vaccine guidance, exposed people who are not immune may receive MMR vaccine within 72 hours or immune globulin within six days, depending on age and immune status.
Timing is the reason to call immediately. Families of infants, children with weakened immune systems, or non-immune pregnant people should contact their clinician the same day they learn of an exposure rather than waiting for symptoms. Call ahead before visiting a clinic or emergency room.
Two MMR doses are 97% effective, and CHOP is offering early doses to eligible children. Philadelphia recommends an early "dose zero" for infants 6 to 11 months old before travel to Lancaster, Lebanon, Berks, Dauphin, Northumberland, or York counties.
Early symptoms include high fever, cough, runny nose, and red, watery eyes, followed by a rash that starts on the head and spreads downward. Trouble breathing, dehydration, seizures, or confusion need urgent care, and children with weakened immune systems may not develop the typical rash.
Cost should not block protection. MMR vaccine is available through health care providers, county and municipal health departments, state health centers, federally qualified health centers, and the Vaccines for Children program, which covers eligible children at no cost, according to the state health department. Updated case counts are posted on the state's measles dashboard.
The state began the formal process of requesting CDC Epi-Aid assistance on Sept. 16, and talks continue. Most Philadelphians face little risk from the CHOP exposure, but families of fragile children should confirm household immunity and call a clinician quickly after any exposure.
Developing Story Timeline
Sept. 18, 2026: Pennsylvania reports 767 cases in 38 counties, 150 hospitalizations, and four measles-associated deaths.
Sept. 17, 2026: Philadelphia announces a probable exposure at CHOP, including the NICU, on Sept. 11.
Sept. 16, 2026: Pennsylvania begins the formal process of requesting a CDC Epi-Aid.
Sept. 15, 2026: State health officials confirm two more measles-associated deaths, bringing the total to four.
Late April 2026: The outbreak begins, according to the Pennsylvania Department of Health.
Key Questions Answered
What happened at CHOP?
A visitor later confirmed to have measles spent time in CHOP's NICU West, family lounge, atrium, and cafeteria on Sept. 11. Potentially exposed infants are being offered a preventive antibody product and are being monitored.
How large is Pennsylvania's measles outbreak?
The state reported 767 confirmed cases across 38 counties on Sept. 18, with 150 hospitalizations and four measles-associated deaths. Four cases have occurred in vaccinated people, less than 1% of the total.
Which children face the highest risk?
Infants under 12 months, children with weakened immune systems, and kids with serious heart, lung, or neurologic conditions face the greatest danger. Their protection depends heavily on the immunity of people around them.
What should families do after a possible exposure?
Call a clinician the same day, especially for infants, children with weakened immune systems, or non-immune pregnant people. MMR within 72 hours or immune globulin within six days may prevent or lessen illness.
What symptoms should parents watch for?
High fever, cough, runny nose, and red, watery eyes usually come first, followed by a rash that starts on the head. Children with weakened immune systems may not develop a typical rash.
Where can families get the MMR vaccine in Pennsylvania?
Health care providers, county and municipal health departments, state health centers, and federally qualified health centers offer MMR. Eligible children can get it at no cost through the Vaccines for Children program.
