Pennsylvania measles outbreak tops 1,000 cases, the largest in the US since elimination
Pennsylvania's measles outbreak is now the largest in the US since the disease was declared eliminated in 2000. The state has recorded 1,078 cases this year, and the outbreak shows no sign of ending.
A measles outbreak in Pennsylvania has passed 1,000 cases, making it the largest in the United States since 2000, when the highly infectious virus was declared eliminated in the country. It is also the biggest on record since 1991.
State health officials say 1,078 measles cases have been recorded in 2026 overall. Twelve were identified in January and March, while 1,066 have appeared since April, when the current outbreak began. In the past seven days, 145 cases were logged, and 74 have been added since Monday's update. Of those 74, 40 date from more than two weeks ago and are only now being recorded.
Hospitalizations and deaths
In total, 207 people have been hospitalized and five have died: a newborn, a 6-week-old infant, and people aged 18, 20 and 40. All of the deceased were unvaccinated, and the two infants were too young to be vaccinated.
Earlier outbreaks
Declining vaccination rates across the country have led to a resurgence of measles in recent years. A Texas outbreak that ran from January to August 2025 ended with 762 cases, while an outbreak in South Carolina ended in April with 997 cases, the previous record. Pennsylvania's 1,066 outbreak-linked cases comfortably exceed that. With 34 new infections reported since Monday, the outbreak does not appear close to ending.
Elimination status
Measles was declared eliminated in the US in 2000 after decades of vaccination efforts. The status is earned and maintained when vaccination rates prevent continuous transmission of the virus over a 12-month period. In November, experts at the Pan American Health Organization (PAHO), which serves as the regional office of the World Health Organization, will review data on whether the US has lost its elimination status. Experts widely expect that it has. Canada lost its status in 2025.
