Measles outbreaks are ongoing in pockets of the Mountain West. And case data shows that individuals at highest risk of contracting the virus are those who are unvaccinated.
By the end of 2024, there were 285 cases of measles and 16 outbreaks. However, CDC data painted a dramatically different picture in 2025.Reported cases had risen to 2,144 and outbreaks climbed to 49.. Hundreds of cases were reported in Mountain West states, with the highest numbers in Arizona, Utah and New Mexico..
Nicole Witt, the Assistant Director for Public Health Preparedness in Arizona said the overwhelming majority of cases were found among people not vaccinated.
“Two doses of the MMR (Measles, Mumps & Rubella) are effective. And 9 out of 10 individuals exposed to a person with measles that are unvaccinated will contract measles,” said Witt.
Mohave County, Arizona, which borders both Nevada and Utah, has one of the highest rates in the country. And Witt said Arizona expects to report more people with measles this week.
“We are in an active outbreak. We will be reporting more cases this week. So, I anticipate we’ll continue to see, at least in Arizona, a high number of cases going into 2026.”
According to the CDC, 95% of a community needs to be vaccinated to provide herd immunity. The U.S. is on track to lose its measles “elimination” status–breaking a 25 year record. Elimination status means there have not been large outbreaks or uncontrolled domestic transmission of a virus in the 12 months before it was declared eliminated, according to KPP, an independent national health information organization.
Measles vaccination rates in Mountain West states, according to the CDC:
Arizona: 89.3%
Colorado: 88.3%
Idaho: 79.6%
Nevada: 91.9%
New Mexico: 95%
Utah: 88.8%
This story was produced by the Mountain West News Bureau, a collaboration between Nevada Public Radio, Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio, KJZZ in Arizona and NPR, with additional support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
