THURSDAY, Sept. 25, 2025 — One of the largest measles outbreaks in decades is spreading along the Arizona-Utah border, with dozens of confirmed cases among unvaccinated children.

Southwest Utah has reported 27 cases so far, nearly all in unvaccinated school-age children, local health officials said. Neighboring Mohave County, Arizona, has 42 confirmed cases, including one child who has been hospitalized.

“This is the highest number of cases we have seen since the 1990s," the Arizona Department of Health Services said.

Experts said the outbreak owes to low vaccination rates.

In Washington County, Utah, about 79% of kindergartners are protected against measles — far below the 95% level needed for herd immunity.

At one school in Mohave County, 7.7% of kindergartners were vaccinated last school year, NBC News reported.

“I’ve worked for this health department for about 18 years, and we’ve never seen a case of measles that I know of up until this point,” David Heaton, a spokesman for the Southwest Utah Public Health Department, told NBC News.

“We are just at that low rate of (vaccine) uptake that does leave us open for this kind of an outbreak,” he added.

Measles is one of the world’s most contagious viruses. Symptoms include fever, cough, runny nose and rash, and the infection can lead to serious complications such as pneumonia, brain swelling and even death, the Mayo Clinic says.

And cases are climbing. The U.S. Centers for Disease Control and Prevention (CDC) has logged 1,514 cases and 40 outbreaks so far in 2025, the most in more than 30 years.

In all of last year, 16 outbreaks were reported.

"This is exactly what you expect to see when you have a highly infectious vaccine-preventable disease drop into a community with low vaccination rates, almost inevitable," Dr. Bob England, a former Arizona public health official, told NBC News.

Federal health leaders are urging families to get vaccinated.

"I encourage parents to vaccinate their children. Vaccines not only protect individual children from measles but also contribute to community immunity," Jim O’Neil, acting CDC director, said.

More information

The U.S. Centers for Disease Control and Prevention has more on the current measles situation.

SOURCE: NBC News, Sept. 22, 2025