US measles cases more than double as Pennsylvania outbreak turns deadliest in decades

The United States is experiencing its worst measles resurgence since the virus was declared eliminated in 2000, with more than 4,580 cases reported in 2026 — more than double the total for all of 2025. The outbreak is centered in Pennsylvania, which has recorded at least 1,338 cases and five deaths, making it the largest and deadliest outbreak in the U.S. in over 30 years Source: NPR, CNN.

The Pennsylvania epicenter

Pennsylvania's outbreak has been particularly severe, with a death rate at least 1.5 times higher than the historical average of 1–3 deaths per 1,000 unvaccinated cases Source: CNN. The state has reported over 250 hospitalizations, and a sixth death is under investigation Source: NPR. A disproportionate share of cases — about two-thirds — are among adults, all but a few unvaccinated, contrasting with the national trend where over 60% of cases are in children Source: CNN. The outbreak has heavily impacted Amish and Mennonite communities in Lancaster and Mifflin counties, which have low vaccination rates Source: NPR, Al Jazeera.

Disagreements over death counts and transparency

State and federal officials are at odds over how to classify measles-associated deaths. Pennsylvania has reported five deaths, while the CDC has only confirmed three nationally and has refused to disclose the location of the third death Source: The Guardian. Health Secretary Robert F. Kennedy Jr. reportedly asked senior CDC officials in September to remove a measles death from the official tally, questioning whether the disease contributed to the death Source: The Guardian. Experts criticize the CDC for lack of transparency, and the agency has sent a "disease detective" to Pennsylvania to better understand the outbreak's true scale Source: CNN, The Guardian.

Broader concerns and response

Vaccination coverage among U.S. kindergartners has dropped from 95.2% in 2019–2020 to 92.4% in 2025–2026 Source: Al Jazeera. In Pennsylvania, more than 39,000 measles vaccines were administered in the first three weeks of October — well above the monthly average of 25,000 Source: NPR. New York Governor Kathy Hochul declared a disaster emergency on October 5, and Utah and South Carolina have also reported large outbreaks Source: NPR, Al Jazeera. Experts warn that declining vaccination rates in one region can leave people thousands of miles away vulnerable, making measles prevention a shared global responsibility Source: Al Jazeera.