Pennsylvania measles cases near 800 in ongoing outbreak

Pennsylvania recorded nearly 100 new cases of measles in the last week, bringing the total case count for this year to 792, state officials said Monday.

The state’s measles outbreak is the largest in the country in 2026 and is centered in Lancaster County, which has reported more than 300 cases this year.

Chester County has confirmed 76 measles cases so far this year, the third-highest total in the state behind Mifflin County in Central Pennsylvania, which has reported 93 cases.

State officials have reported four deaths associated with the outbreak: two infants in Lancaster County, a 40-year-old woman in Jefferson County, and an 18-year-old in Mifflin County.

The state defines a “measles-associated” death as one that occurs within 30 days of symptom onset in a person with clinical evidence of infection and a positive laboratory test for measles, and who did not die of another unrelated cause, like a car crash.

Lancaster County’s coroner said one of the infants died from a lacerated spleen, not measles, though the baby tested positive for the disease. Physicians have noted that measles can weaken a spleen and make it more vulnerable to rupture.

Federal officials have clashed with the state over its characterizations of the deaths.

Democratic Gov. Josh Shapiro has faulted President Donald Trump’s Health and Human Services secretary, Robert F. Kennedy, Jr., a longtime anti-vaccine activist, for spreading misinformation about the safety of the measles vaccine and contributing to declining vaccination rates.

Kennedy, in turn, suggested Shapiro’s administration “fabricated” two of the deaths, though he later acknowledged one death was caused by measles.

The Centers for Disease Control and Prevention still has not listed the deaths on its data dashboard for measles outbreaks.

Officials there have suggested the state is not cooperating with the agency and said officials had not requested emergency help from its Epi-Aid program, which provides short-term technical assistance and subject matter expertise during health crises, as other states with outbreaks have. Trump, in a White House appearance with Kennedy on Friday, called Shapiro “close to incompetent.”

“Incompetence is denying the tragedy of four measles-associated deaths in Pennsylvania,” Shapiro wrote on X in response.

Pennsylvania health secretary Debra Bogen said last week the state was already working with CDC staff, and had begun the process of requesting an Epi-Aid team — on the condition that the agency acknowledges the deaths in Pennsylvania.

Chester County is the only county in the Philadelphia area that has reported measles cases in the current outbreak, which began in April. (Montgomery County confirmed three cases in a separate outbreak in the winter.)

But Philadelphia health officials have reported two potential measles exposures, at the Children’s Hospital of Philadelphia and the Philadelphia International Airport.

On Sept. 11, city health officials said, a person with measles visited a neonatal intensive care unit and several other areas at the hospital at 3401 Civic Center Blvd. in University City. Infants exposed in the NICU were isolated and treated with antibodies to help decrease their chances of acquiring or becoming seriously ill from the highly contagious disease, CHOP officials said.

Two days later, on Sept. 13, a person with measles traveled through Terminals B and F at the airport, as well as areas connecting to Terminals C, D, and E, health officials said. The potential exposure was unconnected to the CHOP incident.

Measles infects up to nine in 10 unvaccinated people exposed to it, and young children are at particular risk for complications from the virus, which can include pneumonia and brain swelling.

About 95% of a community must be vaccinated against the virus to prevent its spread, but vaccination rates across Pennsylvania have been dropping for years. Hundreds of kindergartens in the Philadelphia region report vaccination rates well below this “herd immunity” rate.

State officials said in a statement Monday that more Pennsylvanians have expressed interest in getting vaccinated as the outbreak spreads.

The health department will offer free measles, mumps, and rubella vaccinations from Sept. 26 through Oct. 3 at the Bloomsburg Fair in Columbia County, which has reported two measles cases.

The clinic is “just the latest way the department is meeting Pennsylvanians where they are, to ensure they have the facts and evidence to make decisions about vaccination for themselves and their family,” officials said.

State workers have hosted 148 pop-up vaccination clinics and given out more than 4,800 MMR vaccinations in affected areas since April, with “dozens” more scheduled in the weeks and months ahead, officials said, “based on community interest and need.”

Other healthcare providers have also seen renewed interest in vaccination this year, state officials said. Typically, providers give out about 25,000 MMR doses a month, but in August, more than 46,000 doses were administered, and more than 25,000 doses were given out in the first two weeks of September.