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 since measles was eliminated in 2000.
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.”