A measles outbreak near the Arizona-Utah border that began in August has surpassed 500 cases, new state numbers show.
The outbreak since August 2025 has totaled 516 cases to date — 274 in Arizona and 242 in southwest Utah, according to data from both states as of April 2. State health officials in Utah and Arizona have confirmed a total of 43 hospitalizations and no deaths from the outbreak.
Case numbers in Mohave County on the Arizona side of the state border appear to have slowed, but cases continue to rise in southwest Utah, as well as in Utah as a whole, data shows. The cases are primarily from in and around the twin communities of Colorado City, Arizona, and Hildale, Utah.
While the early Utah outbreak was centered around the state border with Arizona, “we are now seeing community spread across the whole state of Utah,” Charla Haley, assistant communications director for the Utah Department of Health and Human Services, wrote in an email.
“And, while most of our cases stem from this original border outbreak, they aren’t necessarily tied directly to it or the community.”
New measles cases confirmed in Coconino County
Utah health officials, as of April 2, had confirmed 362 cases of measles to date in 2026, with 142 cases reported during the past three weeks.
By comparison, Arizona has confirmed 71 cases in 2026. Sixty of the Arizona cases to date have been in Mohave County. In 2025, Arizona confirmed 220 measles cases, the highest number in the state in more than three decades.
Utah has had more than three times the number of measles cases as Arizona so far in 2026. Utah’s population, at about 3.5 million, is approximately 54% smaller than Arizona’s estimated 7.6 million.
Health officials in Coconino County in northern Arizona recently confirmed the county’s first measles cases of 2026 and named public exposure sites in Page and in Tuba City, which is on the Navajo Nation. The cases at this time have not been linked to the Mohave County outbreak, Arizona Department of Health Services spokesperson Magda Rodriguez wrote in an email.
Exposure sites from the Coconino County cases, which were confirmed March 20 and March 30, include the Tuba City Regional Health Care emergency department, Banner Page Hospital, the Safeway in Page, a Page Unified School District bus, Manson Mesa High School in Page and Page High School.
“If there is a broader public health risk or a need for community notification, we will share that information promptly,” Coconino County Health and Human Services spokesperson Trish Lees wrote in an email.
“We continue to work closely with state and tribal partners as appropriate to monitor the situation and support prevention efforts, including case investigation, contact notification, and public education regarding measles symptoms, exposure and vaccination.”
Arizona-Utah measles outbreak one of the country’s largest in 2025
The Arizona-Utah flare-up was one of three major U.S. measles outbreaks in 2025. The other two were in Texas and South Carolina. Three deaths have been connected with the Texas outbreak, and the upstate South Carolina outbreak is ongoing, with 698 cases reported in 2026, according to the Johns Hopkins Bloomberg School of Public Health U.S. Measles Tracker.
Outbreaks are occurring in tandem with increased public distrust in science and vaccine skepticism from the Trump administration, including the U.S. Health and Human Services Secretary Robert F. Kennedy Jr. The U.S. is currently at risk of losing its measles elimination status, which it achieved in 2000. Elimination means no continuous spread of the virus for 12 or more months.
Both Utah and Arizona allow parents to exempt their children from school-required vaccinations, including the MMR — measles, mumps and rubella — for personal belief or religious reasons.
Utah and Arizona were among 17 states in the 2024-25 school year where 5% or more of kindergarteners claimed an exemption from the MMR vaccine, which means they did not have community protection against measles. The target for MMR coverage is 95% coverage to provide “herd immunity” or group protection from measles, which is an extremely contagious virus.
California, New York, New Mexico, Maine and Massachusetts are among the states that do not allow personal or religious belief exemptions, and all had herd immunity against MMR during the 2024-25 academic year, according to KFF, a nonprofit health policy research organization.
Most Arizona and U.S. parents continue to vaccinate their children, and recent polls have shown that most Americans believe that childhood vaccines are effective at preventing serious illness.
Reach health-care reporter Stephanie Innes at stephanie.innes@usatodayco.com or follow her on X: @stephanieinnes or on Bluesky: @stephanieinnes.bsky.social.
This article originally appeared on Arizona Republic: Arizona-Utah measles outbreak surpasses 500 cases