The deaths are the first from measles reported this year and the first in Pennsylvania in 35 years.
The state health department said the two people, who were not identified other than being residents of Lancaster County, had not been vaccinated against the disease.
Lancaster is home to a large Amish population, a group of traditional agrarian people, who have lower vaccination rates than broader American society.
The deaths come after three people, including two children, died of the disease in 2025, when the outbreak began.
Measles was declared eliminated in the United States in 2000, but it has made a strong comeback in recent years amid newfound vaccine scepticism and growing distrust of health authorities.
US President Donald Trump’s health secretary, vaccine sceptic Robert Kennedy Jr, is accused of contributing to the crisis by stoking fears about the vaccine.
“In 2026, decades after measles was eliminated in the United States, it is heartbreaking to witness deaths from a disease that is preventable with a vaccine that has been widely used since the 1970s,” Andrew Racine, president of the American Academy of Paediatrics, said in a statement.
“Paediatricians call on our leaders to encourage MMR vaccination to stop the spread of measles,” he wrote, referring to the measles, mumps and rubella vaccine.
“Let us return to a time when measles was a disease paediatricians only saw in their textbooks, not in their exam rooms.”
More than 2,770 confirmed measles cases have been recorded in the United States in 2026, surpassing 2025’s total of 2,289 cases, according to the Centres for Disease Control and Prevention.
The previous high for a year was 1991, with 9,643 cases.
Early symptoms of the measles virus include fever, cough and runny nose, followed by a rash a few days later. It can lead to more serious complications such as pneumonia and inflammation of the brain, which can cause severe lasting damage or even death.
Before the vaccine was developed in the early 1960s, measles killed hundreds of children each year in the United States and continues to kill tens of thousands of people worldwide.
Although vaccination is mandatory in the United States, Americans in much of the country can circumvent the requirement by citing religious or, in some cases, philosophical reasons.
Such non-medical vaccine exemptions have surged since the Covid-19 pandemic amid an explosion of vaccine misinformation as well as distrust of health authorities and institutions. (AFP)
