Pennsylvania recorded 1,004 confirmed measles cases and 198 hospitalizations this year, surpassing South Carolina to drive the nation’s largest outbreak in three decades. State health officials confirmed five deaths as low childhood immunization rates and widespread vaccine misinformation continue to fuel community transmission across 39 counties.
Pennsylvania’s 1,004 measles infections surpassed South Carolina’s 997 cases recorded earlier this year, establishing the most severe outbreak the United States has experienced since the early 1990s. State health authorities confirmed the tally crossed the 1,000-case threshold with more than 99% of infected individuals having not received the vaccine; four cases occurred in vaccinated residents.
The Centers for Disease Control and Prevention reported 3,887 measles cases nationwide as of October 2, a 6.2% increase from the previous week. By early October 2026, the CDC counted confirmed cases in 45 states plus Washington, DC. Officials note actual totals are likely higher because only cases confirmed by doctors and reported to federal agencies are officially tallied.
In 2025, infections hit a 30-year peak with 2,289 confirmed cases across Washington, DC, and 43 states for the full year.
Pennsylvania’s 1,004 cases span 39 counties. No other state has reported more than 1,000 measles cases in 35 years, since New York City alone confirmed 2,000 cases in 1991. The current outbreak has resulted in 198 hospitalizations, a rate of nearly 20%.
Lancaster County Drives Regional Spread
Lancaster County accounted for nearly 40% of all Pennsylvania cases by early October. Infections are believed to be concentrated primarily among the Amish or similar religious groups who have historically shown low rates of uptake for the measles, mumps, and rubella vaccine. Because Lancaster County does not have its own local health department, the state manages its cases directly.
Lancaster County contains the largest Amish population in the country, with approximately 44,000 residents as of 2025. Experts point out that nothing in the religion is inherently anti-vaccine, but historical vaccination rates have remained lower than those of the general population. Franklin County and other surrounding areas have noted that diseases do not respect borders, operating under the assumption that the virus will find non-Plain community members who lack immunity.
At the Central Pennsylvania Clinic in Belleville, located in hard-hit Mifflin County, staff meet families at the door to collect samples to avoid facility constraints. A throat swab, a blood sample, and a urine sample are required to confirm a measles case in Pennsylvania. These requirements create arduous tasks for clinicians and for ill patients taking taxing horse and buggy rides to reach the clinic’s large parking lots.
“We might usually have maybe one patient who’s admitted for their complex care needs, but to have so many all at the same time, it’s really unprecedented.”
Dr. Helge Hartung, Central Pennsylvania Clinic, via CNN
Medical personnel regularly make house visits for patients whose health conditions or financial situations make travel difficult. Patients increasingly request home visits because fear of infection keeps them inside. Clinic staff also travel to patients’ homes to administer MMR vaccines upon request.
Adults Face Higher Infection Rates
Only 32% of reported measles infections in Pennsylvania were diagnosed in children under 18 years old. The largest numbers of cases occurred in people ages 25 to 49. This differs from the era before the vaccine, when most infected people were under 5 years old and virtually everyone was immune by age 15.
Approximately 18% of pediatric cases have needed hospitalization. Children can feel very sick, very nauseous, with abdominal pain and vomiting, leaving them unable to take a bottle or keep food or liquid down. Some develop severe and irreversible neurological damage because of brain inflammation, or encephalitis. The Pennsylvania Department of Health has also confirmed that at least 50 pregnant women in the state have contracted measles during the outbreak.
The outbreak has been linked to five deaths in Pennsylvania, the state’s first measles-associated fatalities in 35 years. These five individuals include infants, a 40-year-old woman, an 18-year-old, and a 20-year-old with leukemia. Specialists point out that the fatalities occurred either in adults or in newborns who were infected by adults.
State Expands Vaccination Clinics
State health officials have administered nearly 5,200 MMR vaccinations across 156 pop-up vaccination clinics in affected communities since the outbreak began in late April. The Pennsylvania Department of Health announced it is working with community organizations and healthcare providers to provide access to fact-based information and vaccines. Dozens of additional clinics are scheduled based on community need.
The MMR vaccine, administered over two doses, provides 97% lifetime protection. According to the CDC, the first dose is generally given to children between 12 and 15 months of age, followed by a second dose between 4 and 6 years of age. Individuals with two documented doses do not need another, while adults with only one dose or missing records should consult a healthcare provider or pharmacist.
Reaching herd immunity requires a vaccination rate of at least 95% among kindergartners. Pennsylvania permits exemptions for medical, philosophical, or religious reasons. Nationwide and state-level MMR vaccination uptake has declined in recent years, leaving a growing number of regions without rates consistent with herd immunity.
Local health supervisors note that contact tracing and compliance with isolation protocols are challenging, as individuals are often reluctant to stay home for the recommended 21-day period. Readers seeking guidance or suspecting they have been exposed to measles should contact a qualified healthcare professional or call the Pennsylvania Department of Health’s toll-free hotline at 877-PA-HEALTH (877-724-3258).
