The Utah measles outbreak, now in its 11th month with 679 confirmed cases, has spread from communities along the Utah-Arizona border to every health district in the state, according to state health officials. The long duration of the outbreak has put the U.S. on track for a potential loss of its measles-elimination status, a designation the country has held since 2000.
The U.S. recorded 2,144 measles cases in 2025 — the highest annual total since 1991 — and has already reported 2,073 cases in the first five months of 2026, putting this year on pace to exceed last year’s total. The Centers for Disease Control and Prevention is assessing whether any outbreak has lasted more than 12 months, which is a key criterion the World Health Organization uses to determine whether a country has eliminated measles.
“Really, it did spread everywhere,” said Dr. Leisha Nolen, Utah’s state epidemiologist.
State health officials suspect there has been continuous spread since at least August 2025. The Utah outbreak has proven more difficult to contain than recent outbreaks in Texas, South Carolina and Arizona, in part because the virus spread beyond close-knit, undervaccinated communities to the general population, Nolen said.
The highly contagious disease spread rapidly across undervaccinated communities along the Utah-Arizona border last summer, then reached other areas through events including a high school wrestling championship tournament in February. Utah officials reported exposures at elementary schools, churches, an aquarium, Walmart stores, a ski resort and a youth gymnastics meet. Local health departments have alerted residents to potential exposures at doctors’ offices.
Dr. Trahern W. Jones, a pediatric infectious disease specialist in Utah, said the outbreak did not happen by chance. “This outbreak is the product of years of miscommunication and misinformation,” Jones said.
Jones said he has interviewed families whose children were infected. He described them not as antivaccine activists but as parents who did not understand the severity of measles or who believed vaccines could cause autism — a claim that has been repeatedly refuted by medical research.
“You can see in a mother’s eyes the regret and the shame and the embarrassment and the fear,” Jones said. “You don’t want families to go through the hell of a vaccine-preventable disease to get them to vaccinate.”
Vaccination rates in Utah have declined. The percentage of kindergartners receiving the measles, mumps and rubella (MMR) vaccine fell nearly 10% over 13 years. About 10% of Utah’s kindergartners received nonmedical exemptions for one or more vaccines during the 2024-25 school year — the second-highest rate of any state, behind Idaho, according to CDC data. While several childhood vaccines including MMR are required for school enrollment in Utah, parents can opt out for religious or personal reasons.
The county health department in Provo told Aubrey Johnson, 28, that her newborn might have been exposed to measles at her pediatrician’s office around Thanksgiving, she said. Her son was just 1 week old at the time and too young to be vaccinated. Johnson delayed visits from her parents, in-laws and grandmother as she monitored him for symptoms.
“Is that red spot on his head a rash or a birthmark I didn’t notice?” Johnson recalled thinking. “It just heightened the anxiety of it.” Johnson’s son recently turned 6 months old and received an early dose of the MMR vaccine, which pediatricians recommend for infants in outbreak areas.
Utah’s public health response has differed from other states’ approaches. In South Carolina, the state health department required students exposed to measles to quarantine for three weeks. Hundreds of students were out of school at a time. South Carolina declared its outbreak over in April.
In Utah, local health departments operate independently from the state. The Southwest Utah Public Health Department struggled to persuade parents to vaccinate their children despite the spread, said David Heaton, the department’s spokesman. While some school districts encouraged unvaccinated students who had been exposed to measles to stay home for three weeks, the decision was left to parents, and the health department does not know who complied, Heaton said.
The World Health Organization considers measles eliminated in a country when there is no endemic spread for at least 12 months under a robust tracking system. The U.S. achieved that status in 2000 through a widespread vaccination campaign. The Pan American Health Organization, the group that decides where the U.S. stands, is scheduled to meet in November.
One new measles case was reported last week by the Utah Department of Health & Human Services. The state must record no new cases over 42 days — two incubation periods — to consider the outbreak over.