Measles cases rise in Canyon County; health officials warn eastern Idaho of risk

POCATELLO, Idaho (KIFI) — Health officials are reporting five probable measles cases in Canyon County, all within a single unvaccinated household, as they work to prevent the virus from spreading in local schools and the wider community.

Lakshmi Venugopal, an epidemiologist with Southwest District Health, said the cases are being treated as measles based on the patients’ symptoms and their recent travel history, even though lab confirmation is pending.

“We have had five probable cases of measles here in Canyon County,” she said. “Given their clinical history and history of exposure to measles during travel, it’s considered to be measles.”

The family’s exposure occurred during out-of-state travel over the winter break. Because measles can take up to 21 days after exposure to cause symptoms, the children began showing signs of illness after returning to Idaho.

Two of the children attended school in Caldwell while infectious — one at Vallivue Middle School on Jan. 9 and another at Vallivue High School on Jan. 20. Southwest District Health has been working with school officials to notify parents of potentially exposed students and to monitor for symptoms.

“We are closely monitoring all the children in these two schools,” Venugopal said. “If anybody shows symptoms, we’ll be working with them to make sure they are getting connected with a provider, getting testing if needed, and getting recommendations on how long they should stay home before going back to school.”

Statewide, Idaho has recorded 21 measles cases across six counties, including the Canyon County cluster. Boundary County has reported the highest number of cases since August 2025 with six. Eastern Idaho has reported measles cases this year from Madison County; however, due to the time it takes for symptoms to fully manifest, they have not yet been confirmed.

Ian Troesoyer, a nurse practitioner and epidemiologist for Southeastern Idaho Public Health, said Idaho is at a crossroads.

“Idaho is dead last in the nation for measles vaccination coverage for kindergarteners, which means we’re at one of the highest risks for one of the most vulnerable populations,” Troesoyer said. “Measles is the most contagious illness we know of.”

With Idaho’s low vaccination rate, he warned that eastern Idaho may be more vulnerable to a significant outbreak than other regions.

“We are worried about measles cases in our own state and from adjoining states coming into our district,” he said. “People from southeastern Idaho and eastern Idaho are going down to Salt Lake all the time. What is happening in Utah could easily show up here.”

According to Troesoyer, even a small number of cases could strain the capacity of the state's pediatric hospitals.

“If your kid is not vaccinated and they get exposed to measles, they are very likely going to get it, and then there’s like a one-in-five chance they could be hospitalized,” he said. “Now that we know there’s measles circulating in Idaho, I would strongly encourage you to consider getting them vaccinated.”