(ATLANTA, July 10, 2025) — The U.S. is facing its worst measles outbreak in over three decades, with cases surpassing 1,280 by mid-year and health officials linking the surge to declining MMR vaccine coverage.
According to the Centers for Disease Control and Prevention (CDC), 1,288 confirmed measles cases have been reported so far this year, spanning 39 states. This marks the highest number of infections since 1992, with cases already exceeding the 2019 total of 1,274. Texas is currently the hardest-hit state, reporting over 750 cases, followed by clusters in Florida, Arizona, Kansas, Montana, and North Dakota.
Health authorities have identified 27 separate outbreaks in 2025—up from just 16 last year. Nearly all infections—over 92%—have occurred in individuals who were either unvaccinated or whose vaccination status is unknown. Children under the age of five represent 29% of all cases, while children and teens between the ages of five and nineteen account for another 36%. Hospitalization has been required in about 13% of cases, and at least three deaths have been confirmed, including two children in Texas and an adult in New Mexico.
The resurgence of measles is being closely linked to falling rates of MMR (measles, mumps, and rubella) vaccination. While national coverage among kindergartners remains around 93%, it falls below the 95% threshold required to maintain herd immunity. In some communities, vaccine uptake has slipped as low as 88%, leaving large pockets of the population vulnerable.
Health experts warn that misinformation—often spread online—is a key driver of this trend. Presidential candidate Robert F. Kennedy Jr., who has a long history of questioning vaccine safety, is frequently cited as a prominent source of false claims. Kennedy, who denies being “anti-vaccine,” has repeatedly promoted discredited theories linking vaccines to autism. Imran Ahmed, CEO of the Center for Countering Digital Hate, told the Associated Press that Kennedy has been “one of the biggest megaphones for vaccine falsehoods.”
Measles was declared eliminated in the United States in 2000, but health officials now warn that status is at risk. Even a single imported case can trigger widespread outbreaks in areas with declining vaccination rates. Dr. Sean O’Leary of the American Academy of Pediatrics said the situation underscores a critical public health failure: “We’re seeing the real consequences of misinformation. Measles is back, and it’s entirely preventable.”