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The United States has surpassed 1,100 measles cases in just the first two months of 2026 — a troubling milestone that public health experts say signals a worsening national crisis driven largely by low vaccination rates.
Data released Friday by the Centers for Disease Control and Prevention (CDC) show 1,136 confirmed cases as of Thursday (February 26) — six times more than what the country typically sees in an entire year. More than half of US states have reported at least one case, and at least three large outbreaks are actively growing across the country.
About 96% of cases this year involve people who were either unvaccinated or did not receive both recommended doses of the measles-mumps-rubella (MMR) vaccine. More than 80% of cases are among children and teenagers, with roughly one in four involving children under five years old.
According to the CDC, for every 1,000 children infected with measles, up to three may die and one may develop encephalitis — a dangerous swelling of the brain.
Last year, the US reported nearly 2,300 measles cases — the most in a single year since 1991. Three people died: two children in Texas and one adult in New Mexico, all unvaccinated.
The nation's largest active outbreak is centered in the upstate region of South Carolina, particularly Spartanburg County, where vaccination rates are especially low. South Carolina Department of Public Health data shows at least 979 cases since the outbreak began in October, making it the largest US measles outbreak in more than 30 years.
Severe complications — including pneumonia and encephalitis — have been reported, and several pregnant women required protective treatment after exposure. No deaths have been reported in the state.
The state administered nearly 17,000 MMR vaccines in January, one of the most successful vaccination months in years. About 90 state health department staff members are currently dedicated to the outbreak response, with roughly a third focused on contact tracing.
Multiple states have reported cases linked to the South Carolina outbreak, including North Carolina, Washington, and California. North Carolina has logged 23 cases since December — more than five times the total it recorded over the entire past decade.
A separate outbreak along the Utah-Arizona border continues to grow, and a more recent outbreak in Collier County, Florida, has surged over the past month. That outbreak is centered around Ave Maria University, a private Catholic college in a planned community, with at least 83 cases reported in the county.
Measles was declared eliminated in the US in 2000, but the ongoing surge threatens that designation. The Johns Hopkins University Center for Outbreak Response Innovation, which tracks outbreak data independently, has tallied an even higher case count than the CDC's official figure.
The Pan American Health Organization is set to meet in April to formally assess whether the US will retain its measles elimination status.
Experts urge parents to speak with their children's doctors about vaccination.