An unvaccinated 40-year-old woman from Jefferson County, Pennsylvania, has died of complications from measles, county officials said, becoming the third measles-linked death reported in the state in less than three weeks and the latest marker in the largest U.S. measles outbreak in 35 years.
The woman, who had asthma and chronic obstructive pulmonary disease and relied on supplemental oxygen, developed fever and a rash before she died on Saturday, Sept. 12, according to the Jefferson County coroner's office. Chief Deputy Coroner Jason Stiver said she "did have a pretty extensive medical history" and was on oxygen around the clock; a nasal swab confirmed an active measles infection at the time of death. Her death follows those of two infants in Lancaster County last month, one of them stillborn after his mother went into early labor during a measles infection.
"This is a heartbreaking loss for the family and an unfortunate reminder that measles can be a serious and potentially life-threatening disease."
— Coroner Greg Furlong, Jefferson County
Cases climbing statewide and nationally
Pennsylvania had confirmed 693 measles cases as of Monday, including nearly 100 added in the previous week alone, with 124 hospitalizations tied to the outbreak, according to state health department figures reported by NBC News. Nationally, the Centers for Disease Control and Prevention had logged 3,294 confirmed cases as of Sept. 10 — the country's highest measles count since 1991, before the disease was declared eliminated domestically in 2000. The CDC said 93% of this year's cases involve people who are unvaccinated or whose vaccination status is unknown, and 38 separate outbreaks, each requiring three or more linked cases, have been recorded in 2026. The agency has not yet listed measles as the underlying cause of any 2026 death in its national vital-statistics records; state coroner findings such as Jefferson County's typically take weeks to be reflected in that federal count.
Health officials tie the surge to sliding vaccination rates: CDC data show measles, mumps and rubella vaccine coverage among kindergartners has fallen to 92.4%, below the roughly 95% threshold generally considered necessary to prevent sustained community spread. The MMR vaccine is about 97% effective at preventing infection after two doses, and outbreaks have concentrated in under-vaccinated communities in Pennsylvania and several other states this year.
Pennsylvania's health department has expanded free vaccination clinics in the affected counties and urged residents who are unsure of their immunization status to contact a provider. Federal and state officials say they expect case counts to keep rising into the fall as the current outbreaks, several of them linked to school-age children, continue to spread through communities with vaccination coverage below the threshold needed for herd immunity.
