Pennsylvania's health department reported 977 confirmed measles cases across 39 counties as of Friday, October 2, pushing the state's outbreak to the brink of a grim four-digit milestone. Thirty-four new cases emerged in just two days between September 30 and October 2.
This is the worst measles outbreak the United States has seen in more than three decades. Since the outbreak began in April, at least 195 patients have been hospitalized. All but four of the confirmed cases involved people who were not fully vaccinated.
The death toll is climbing as well. On Wednesday, September 30, the Pennsylvania Department of Health announced the year's fifth measles-associated death: an unvaccinated Lancaster County resident who tested positive for the virus. The state counts a death as measles-associated when it occurs within 30 days of symptom onset with a positive test; officials declined to release further identifying details.
The four earlier deaths included two infants from Lancaster County, a 40-year-old woman from Jefferson County, and an 18-year-old from Mifflin County who died of acute disseminated encephalomyelitis, a rare neurological complication. The state says all five people who died this year were unvaccinated.
Lancaster County is the epicenter of the outbreak, accounting for roughly 40 percent of the state's cases. The county is home to the nation's oldest Amish and Mennonite communities, where vaccination rates have long been low. Public health researchers note that many unvaccinated Amish residents are not firmly opposed to vaccines — they simply have not found it convenient to get them. Nurses are now going door to door through Amish communities to deliver vaccinations.
Pennsylvania's fragmented public health system has complicated the response. Only seven of the state's 67 counties have their own health departments, and Lancaster County — the epicenter — is not among them, which slowed the early response. Neighboring Chester County, which does have a health department and the state's third-highest case count at 83, is now preparing for an influx of cases from across the border. "We have a very long border with Lancaster County, and these types of diseases don't respect borders," said Jeanne Franklin, director of Chester County's health department.
The outbreak has also triggered a dispute between state and federal officials. Pennsylvania Department of Health Secretary Dr. Debra Bogen requested help through the CDC's Epi-Aid program, but warned the state would rescind the request "if CDC is unable to transparently and accurately communicate information about those measles-associated deaths." The CDC's dashboard confirms only two measles-related deaths nationwide this year, without naming the states, and says it is working with state epidemiologists on a standard case definition for measles deaths.
Measles is one of the most contagious viruses known. It spreads when an infected person coughs, sneezes, or breathes in an enclosed space, and the virus can linger in the air and on surfaces for up to two hours after an infected person leaves. Symptoms typically begin with high fever, cough, runny nose, and red or watery eyes, followed by a rash that starts on the head and spreads downward. Complications can include pneumonia and inflammation of the brain.
Vaccination remains the most effective protection. Two doses of the measles, mumps, and rubella (MMR) vaccine are about 97 percent effective at preventing measles. Governor Josh Shapiro's administration has expanded vaccination efforts: in September alone, more than 53,000 MMR doses were administered statewide, more than double the typical monthly figure. The health department has also set up pop-up clinics in affected communities.
Nationwide, measles is surging. CDC data shows 3,887 measles cases reported across the U.S. as of October 1 — the highest annual total since 1991 — and Pennsylvania remains the center of the surge. Lancaster County Coroner Stephen Diamantoni, himself a family physician and strong vaccination advocate, warned that fall and winter tend to make respiratory illnesses worse: "So it very well could become much worse." Health officials urge residents to check their vaccination records, and anyone who may have been exposed should call a health care provider before visiting a medical facility in person.