Two people have died of measles in Pennsylvania, decades after the disease was considered eradicated. Measles is currently making a resurgence in the US, with cases at a 35-year high.

The two victims were residents of Lancaster County, a largely rural county west of Philadelphia, state health officials announced on Tuesday. No additional details were provided, except that neither victim was vaccinated.

Fatal cases of measles are exceedingly rare in the US, but infections are rising. 2,289 cases of the disease were recorded in 2025, the highest number since 1991, when 9,643 cases were recorded. Last year’s number was surpassed by this July, and as of August 20, 2,777 cases have been recorded this year, according to the US Centers for Disease Control and Prevention.

Outbreaks have occurred in 47 US states and territories, with 94% of cases occurring among the unvaccinated.

Measles is a highly contagious viral respiratory disease that was officially eliminated in the US in 2000 following a successful mass vaccination campaign. Before mass vaccination began in the 1960s, measles killed between 400 and 500 Americans every year, according to CDC data.

Dr. Adam Ratner, an adviser to the CDC, told the JAMA medical journal last year that skepticism about Covid-19 vaccines has “bled over” into other vaccines, due to the Covid shots becoming “this insanely polarized political thing” from 2020 onwards. 

“Once there was that kind of hesitancy out there and that kind of divisiveness, it’s not surprising that it has bled over into people thinking about vaccine mandates and childhood vaccines in general,” Rather said.

US Health Secretary Robert F. Kennedy Jr., a longtime vaccine skeptic, has vouched for the safety of the combined measles-mumps-rubella (MMR) vaccine, but noted “the decision to vaccinate is a personal one.”

A vaccination rate of around 95% is required to prevent measles outbreaks. In November, the Pan American Health Organization (PAHO), a division of the World Health Organization (WHO), will meet to determine whether the US and Mexico can still claim to be “measles free” after recent outbreaks.