Pennsylvania Measles Outbreak Becomes Nation’s Largest, Reaching 577 Cases

HARRISBURG, Pa. — A measles outbreak centered in Lancaster County has grown into the largest in the United States, with 577 confirmed cases across 37 Pennsylvania counties so far this year, state health officials said.

Lancaster County accounts for 246 of those cases, according to local reporting. The Pennsylvania Department of Health has recorded 98 hospitalizations and two measles-associated deaths, both Lancaster County residents, which were announced in August. They were the state’s first measles deaths since 1991.

Outbreak Began in April

The outbreak began in late April and has spread from communities in Lancaster County to dozens of counties across the state. Health officials have not released identifying details about those who died, citing family privacy.

Health Secretary Dr. Debra Bogen said when the deaths were announced that the losses underscored the department’s efforts to provide information and protection, warning that the virus spreads quickly and easily to anyone who is not immune.

Vaccination Push

Since the outbreak began, state health officials have administered more than 3,900 measles, mumps and rubella vaccinations at more than 100 pop-up clinics in affected communities, with dozens more clinics scheduled. State health center staff have given more than 5,700 MMR doses across Pennsylvania this year.

Demand has surged among health care providers as well. In a typical month, providers in Pennsylvania administer about 25,000 MMR doses; in August, more than 46,000 were given, the department said.

Gov. Josh Shapiro’s administration has also worked with the state Department of Education to provide guidance to schools and has equipped school nurses and clinicians with clinical guidance, noting that many have never handled a measles case.

Highly Contagious Disease

Measles is among the most contagious diseases known. It spreads through the air when an infected person coughs or sneezes and can linger in a room for up to two hours. Symptoms include high fever, cough, runny nose, red eyes and a rash. Complications can include pneumonia, brain swelling and death, particularly among young children.

Two doses of the MMR vaccine are about 97% effective at preventing measles, according to state health officials.

National Context

The United States has seen a resurgence of measles in recent years as vaccination rates have declined in some communities. The country eliminated endemic measles transmission in 2000, a status that public health experts warn is at risk if large outbreaks continue.

The department maintains a public dashboard tracking cases, hospitalizations, deaths and vaccination efforts, and urged residents who are unsure of their immunity to contact a health care provider.