Two people who were not vaccinated against measles have died of the virus in Pennsylvania, health officials said.
The state has seen 393 cases of the highly contagious virus this year, as infections across the US have hit the highest point in 35 years.
Last year, two unvaccinated children in Texas died from a measles outbreak that infected over 1,000 people, primarily children.
Eighty-five percent of kindergarten-age students in Lancaster County, where the recent deaths occurred, are vaccinated against measles – well below the 95% rate needed for herd immunity to limit the spread and protect immunocompromised people.
“My deepest sympathies are with the loved ones who are facing this unimaginable loss,” Pennsylvania Secretary of Health Debra Bogen said in a statement.
“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.”
She added that the mumps, measles and rubella (MMR) vaccine provides the best protection against illness and death. The health department did not share any additional information on the identities of those who died.
The US has seen 2,777 confirmed cases of measles in 2026, just seven months into the year, up from last year’s high of 2,289.
The rising number of cases comes as vaccine hesitancy in the US has increased in recent years, leading to lower immunisation rates. The US recommends two shots to children between ages one and six, which is 97% effective in protecting against the illness.
Earlier this month, President Donald Trump signed an executive order that calls for fewer childhood vaccinations and recommends splitting the MMR vaccine into three separate shots. Public health experts worry the order will cause confusion about an already safe and effective vaccine and prove costly.
The executive order came after Health Secretary Robert F Kennedy Jr took a number of steps to remake US vaccine policies over the past year, including the childhood vaccination schedule. Many of the changes were blocked by a federal judge earlier this year.
A vaccine skeptic, Kennedy has shared mixed messaging on MMR vaccine, at times endorsing it and other times sharing unproven claims about its safety.
The US is on track to lose its status of having eliminated measles, which will be determined by a panel in November. Canada lost its status last year.
