Two unvaccinated people in Pennsylvania have died from measles, as a large outbreak there continues to spread, the state’s Health Department reported on Tuesday morning. They were the first measles deaths this year in the United States.

The deaths come during a record-setting year for measles in the United States: More cases have been reported in 2026 than in any other year since the virus was declared eliminated in 2000. Outbreaks have popped up all over the country. Lancaster County, Pa., where both patients lived, has been at the center of an outbreak that has so far hospitalized 70 people and infected more than 390, a third of whom were children. Health officials, citing privacy reasons, did not say whether the two patients were children or adults.

Measles deaths are extremely rare in the United States. But the virus’s recent resurgence has caused a handful of fatalities. Two school-aged children and one adult died last year from measles complications, the first such deaths in the country in a decade.

“These five deaths that have occurred since 2025 are extremely, extremely rare in the modern era,” said Dr. Amesh Adalja, an infectious disease doctor at the Johns Hopkins Center for Health Security. “They’re also a harbinger of what is happening as this virus takes hold again in the United States.”

The best way to protect against measles is with two doses of a vaccine, which is usually administered to children as a combination measles-mumps-rubella, or M.M.R., shot. Two doses of the vaccine prevent more than 97 percent of measles infections.

Nationwide, routine childhood vaccination rates have been on the decline, dipping below the 95 percent benchmark that experts say is necessary to stave off outbreaks. Within some pockets of Lancaster County, the vaccination rate is much lower: Just a quarter of people within the local Amish community had been vaccinated against measles, according to a 2025 estimate.

While most measles cases are mild, roughly 1 in 5 unvaccinated people in the United States who contract the virus lands in the hospital. The virus is especially dangerous for children. Up to 3 out of 1,000 children with measles die from respiratory and neurological complications, according to the Centers for Disease Control and Prevention. As many as 1 in 20 children with measles goes on to develop pneumonia, which is the leading cause of death from measles among children. In rare cases, children can also experience brain swelling, which can leave them with lifelong hearing damage or intellectual disabilities.

There are no treatments for measles, though researchers are trying to develop some.

“Because measles was largely eliminated in the Commonwealth for more than three decades, people are not familiar with this disease and don’t fully understand the potential severity of the illness,” said Dr. Debra Bogen, Pennsylvania’s health secretary.

This is a developing story. Check back for updates.