Pennsylvania has recorded another measles-related death, bringing the state’s total to four this year.
An unvaccinated 18-year-old from Mifflin County, roughly 150 miles from Pittsburgh, died from measles complications, county coroner Andrea Alcalde confirmed Tuesday.
Alcalde said the teenager, whose identity was not disclosed, developed acute disseminated encephalomyelitis, a rare but serious neurological complication of measles that causes inflammation in the brain.
Authorities did not provide additional information about the teenager.
The announcement followed news that an unvaccinated 40-year-old woman in neighboring Jefferson County died over the weekend from “complications associated with measles,” according to health officials.
Pennsylvania has now reported four measles deaths in 2025, marking the first fatalities linked to the virus in the state in 35 years.
The other two victims were infants from Lancaster County.
As of September 14, Pennsylvania had documented 693 measles cases, including 99 reported during the previous week. The outbreak has led to 133 hospitalizations, while fewer than 1 percent of patients had received both recommended doses of the measles, mumps and rubella, or MMR, vaccine.
An 18-year-old Pennsylvania woman died Saturday after suffering measles-related complications (stock image)
The state Department of Health reiterated that full vaccination remains the strongest protection against measles.
The CDC recommends two MMR doses, with the first typically administered between 12 and 15 months of age and the second between ages four and six. The vaccine is estimated to be 97 percent effective at preventing measles.
Among people who have not been vaccinated, about nine out of 10 individuals exposed to measles are expected to become infected.
“My thoughts are with the two families who lost loved ones to this highly contagious virus, as Pennsylvania faces the worst measles outbreak in more than three decades,” Pennsylvania Secretary of Health Dr. Debra Bogen said Tuesday.
“We remain committed to working with our partners across Pennsylvania to stem this outbreak and prevent more deaths. That means ensuring people have the facts about measles and access to the MMR vaccine—which kept measles outbreaks at bay for decades.”
The state’s first two measles-related fatalities were newborn Ivan S. Miller of Strasburg Township in Lancaster County and six-week-old Mary S. Stoltzfus of Fulton Township.
Neither was old enough to be vaccinated.
CDC data updated September 11 shows 3,294 measles cases nationwide so far this year, well surpassing last year’s total of 2,289. About 95 percent of infections this year have been in unvaccinated individuals.
Measles, which is highly infectious, is characterized by cough, fever, a distinctive blotchy rash that starts on the face before spreading down the body and tiny white spots inside the mouth called Koplik spots.
The virus spreads through direct contact with infectious droplets or through the air. Patients with a measles infection are contagious from four days before the rash through four days after the rash appears. Enclosed areas like airports and planes are extremely risky locations for disease transmission.
It first invades the respiratory system, then spreads to the lymph nodes and throughout the body. As a result, the virus can affect the lungs, brain and central nervous system.
MMR vaccines (center) sit inside a medical refrigerator. The shot is typically given once between ages 12 and 15 months and again between ages four and six
The above CDC map updated September 11 shows measles cases by state for 2026
While measles sometimes causes milder symptoms, including diarrhea, sore throat and achiness, it leads to pneumonia in roughly six percent of otherwise healthy children, and more often in malnourished children.
Though the brain swelling that measles can trigger is rare, occurring in about one in 1,000 cases, it is deadly in roughly 15 to 20 percent of those who develop it, while about 20 percent are left with permanent neurological damage, such as brain damage, deafness or intellectual disability.
Measles also severely damages a child’s immune system, making them susceptible to other potentially devastating bacterial and viral infections they were previously protected against.
Before MMR vaccines became available in the 1960s, measles caused epidemics with up to 2.6 million global deaths every year. By 2023, that number had fallen to roughly 107,000 deaths.
Nationwide, 92.4 percent of kindergarteners are fully vaccinated against measles, below the CDC’s 95 percent threshold for herd immunity. In Pennsylvania, the MMR vaccination rate is 94.6, while rates in Maryland and Iowa are 96 and 90 percent, respectively.
Exemptions are also on the rise at 4.2 percent, up 17 percent from 1.6 percent just over a decade ago.
