Children’s hospital faces ‘biggest measles exposure we’ve ever seen’ after visitors test positive for deadly virus and expose hundreds

A major children’s hospital caring for some of the sickest patients is facing measles exposure after visitors tested positive for the highly infectious virus. 

Two people who visited various locations throughout UPMC Children’s Hospital of Pittsburgh tested positive for measles, which is considered to be the most infectious disease.

Dr Donald Yealy, UPMC’s chief medical officer and chair of emergency medicine, told TribLive Tuesday that the exposure involved a child and two parents who were at the hospital for a scheduled visit on August 27.

The virus remains in the air for two hours after a sick person has passed through and it is able to infect nine out of every ten unvaccinated individuals who are exposed. 

Yealy declined to say whether the hospital visit was measles-related, but health officials said the pair were not Allegheny County residents and left the area afterward.

The potential exposure occurred in the hospital’s main lobby, third-floor waiting and clinic areas, cafeteria and elevators, putting hundreds of people at risk, health officials said. 

‘It is a large number of people, bigger than what we’ve seen before,’ Yealy said.

This is the third confirmed measles case at UPMC Children’s Hospital of Pittsburgh this year.

The first involved a Jefferson County resident who tested positive on August 20 after visiting the hospital on August 12 and 18. It marked the first confirmed measles case in Allegheny County since 2019. 

UPMC is notifying exposed patients and staff, while the Allegheny County Health Department is urging anyone who was in those areas to check their vaccination status and contact a doctor for guidance.

These events come after a hospital in Danville, Pennsylvania, locked down its neonatal intensive care unit (NICU) after a visitor tested positive for measles and the state reported two measles deaths, the first in 35 years. 

Geisinger Medical Center in Danville, a 2.5-hour drive outside Philadelphia, said the visitor was in the unit for four days from August 14 to 17 before the diagnosis.

The NICU cares for premature babies and sick infants who need around-the-clock treatment. Considered the most vulnerable patients in a hospital, these individuals are too young to be vaccinated against measles or virtually any other disease.

Under new rules, only the parents or legal guardians of patients are now permitted to visit the unit.

These visitors must show no signs or symptoms of measles and will be screened upon arrival before being allowed to enter. They are also ‘highly encouraged’ to wear a surgical mask.

At present, there is no exemption for vaccinated immediate family, such as grandparents, that would allow them to also visit the unit.

The infected visitor in Danville is no longer in the unit. It is not clear how long the restrictions will last or whether the visitor passed measles on to anyone else.

The US is currently battling a major measles outbreak, recording 2,903 infections so far this year, the most since 1991, according to CDC figures updated August 27.

State data updated September 2 shows 540 people in Pennsylvania have been infected from the outbreak, none of whom were fully vaccinated. There have been 91 hospitalizations in the state. 

Pennsylvania recorded two deaths linked to measles last week, marking the first in the nation this year and first in the state in 35 years. They were in Lancaster County, which is at the epicenter of the state’s measles outbreak.

The vast majority of cases in both 2025 and 2026 were in individuals who had not received both doses of the measles, mumps and rubella (MMR) vaccine.

The shot is typically given once between ages 12 and 15 months and again between ages four and six. Two doses slash the risk of measles infection by 97 percent, according to the CDC.

For unvaccinated people, nine in ten of those exposed to the virus will get infected.

Measles, which is highly infectious, is characterized by cough, fever, a distinctive blotchy rash that starts on the face before spreading down the body and tiny white spots inside the mouth called Koplik spots.

The virus spreads through direct contact with infectious droplets or through the air. Patients with a measles infection are contagious from four days before the rash through four days after the rash appears. Enclosed areas like airports and planes are extremely risky locations for disease transmission.

It first invades the respiratory system, then spreads to the lymph nodes and throughout the body. As a result, the virus can affect the lungs, brain and central nervous system.

While measles sometimes causes milder symptoms, including diarrhea, sore throat and achiness, it leads to pneumonia in roughly six percent of otherwise healthy children, and more often in malnourished children. 

Though the brain swelling that measles can trigger is rare, occurring in about one in 1,000 cases, it is deadly in roughly 15 to 20 percent of those who develop it, while about 20 percent are left with permanent neurological damage, such as brain damage, deafness or intellectual disability.

Measles also severely damages a child’s immune system, making them susceptible to other potentially devastating bacterial and viral infections they were previously protected against.

Before MMR vaccines first emerged in the 1960s, measles caused epidemics with up to 2.6 million global deaths every year. By 2023, that number had fallen to roughly 107,000 deaths.

Nationwide, 92.4 percent of kindergarteners are fully vaccinated against measles, below the CDC’s 95 percent threshold for herd immunity. In Pennsylvania, the MMR vaccination rate is 94.6 percent, while rates in Maryland and Iowa are 96 and 90 percent, respectively.

Exemptions are also on the rise at 4.2 percent, up 17 percent from 1.6 percent just over a decade ago.