By Zachery Schmidt
The Center Square

The area along the Arizona and Utah border is continuing to see the measles outbreak that started in August, and California and Colorado have seen a number of cases.

Nevada hasn’t seen any, but is monitoring the national trend.

Meanwhile, the Arizona Department of Health Services is concerned about the outbreak and is closely monitoring it, said Dr. Joel Terriquez, the department’s medical director of the bureau of infectious diseases services. He urges people to get vaccinated.

Terriquez told The Center Square that Mojave County is the state’s most affected county.

“The number of measles cases in that area has been significantly higher than any other area of the state,” he noted.

Measles cases that have not been in Mohave County are not associated with an outbreak, but rather “independent clusters of cases,” Terriquez said.

Since the outbreak that started in August, Arizona has a total of 261 cases, he noted, including 56 cases so far this year.

He told The Center Square that 67% of people who have gotten measles have been younger than 18.

On top of this, Terriquez said 97% of people who have gotten measles have been unvaccinated.

He added that despite the concerns of some people, the measles, mumps and rubella vaccine is “very safe and effective.” He said that conclusion is based on decades of research.

“It only takes one vaccine to potentially prevent an outbreak. It takes one vaccine to protect a kid from getting measles and potentially protecting them from complications,” Terriquez said.

Measles among an unvaccinated population is “gonna spread like wildfire,” Terriquez said, noting the disease is “extremely contagious.”

The Centers for Disease Control and Prevention said nearly 89% of people in Arizona are vaccinated against measles.

One dose of the MMR vaccine protects a person against 93% of potential measles cases, while two doses can protect a person up to 97% of potential measles cases, according to Terriquez.

Terriquez noted no one in Arizona who has contracted measles has died from it.

CDC data, which was updated Thursday, shows 1,281 people have contracted measles in 2026. Last year, 2,281 people contracted measles.

In total, 300 people have been hospitalized due to measles. This means that 9% of all measles cases in America in 2025 and in 2026 have resulted in hospitalization.

Terriquez said America last year experienced three measles-related deaths, which is 0.09% of all cases.

According to the CDC, no one has died from measles this year.

Terriquez said the “vast majority of individuals” who get measles “will not develop any complications.” However, if people do develop complications from measles, Terriquez pointed out, it “can be very severe.”

Complications from measles, such as pneumonia, measles encephalitis and meningitis, could potentially kill someone, he explained.

“Long-term complications can come years after the initial measles infection,” with them being “very unpredictable with high mortality,” Terriquez said.

In Arizona’s neighboring state, Utah, there is a measles outbreak.

Dr. Leisha Nolen held a press conference on Thursday to address the spread of measles throughout Utah.

The state has had 358 people diagnosed with measles since June 2025, Nolen told reporters.

According to Nolen, 120 people have gone to the emergency room, with 31 requiring hospitalization overnight. She added that three people have gone to the intensive care unit.

No one in Utah has died from measles, she said.

Nolen said measles is spreading across Utah. She noted the measles cases were initially limited to the southern part of Utah, but have now expanded to every part of the state, largely through school events.

She encouraged people to get vaccinated against measles. The CDC said 89% of people in Utah are vaccinated against measles.

Colorado, meanwhile, has seen fewer measles cases than Arizona and Utah.

Colorado has had eight measles cases in 2026, compared with 36 last year.

Hope Shuler, interim communications director for the Colorado Department of Public Health and Environment’s division of disease control and public health response, said the state has collaborated closely with its local partners.

She told The Center Square this collaboration is meant to “ensure rapid response to any potential transmission.”

Shuler added that they have “conducted thorough case investigations in order to alert the public to potential exposures and provide the steps they can take to protect themselves from further spread.”

Due to the state’s media campaign, website updates and provider webinars, Shuler said Colorado and its partners “successfully drove a 30.55% increase in MMR vaccine doses given compared to 2024.”

“We have also performed direct outreach to families whose children are overdue for their MMR vaccines. In 2025 and 2026, six rounds of outreach to families of children overdue for their MMR vaccines led to 48% of those contacted becoming up-to-date,” she explained.

Colorado’s measles vaccination rate is 88%, the CDC said.

Another state with some measles cases is California. The Golden State has seen 26 confirmed cases in 2026. This amount exceeds the total for all of 2025, which reported 25 measles cases.

Sacramento and Placer counties have reported recent measles incidents. The California Department of Public Health said it was working with those counties to alert people who may have been exposed to measles.

Dr. Erica Pan, CDPH director, urged people to get the MMR vaccine.

“Measles, one of the most contagious infections, can lead to severe life-long consequences including permanent brain damage and can also be fatal, especially for children,” he said.

The CDC noted California’s measles vaccination rate is 96%.

Unlike all these other states, Nevada has not had any measles cases so far this year.

The state actively monitors the nationwide measles situation, said Daniel Vezmar, public information officer for the Nevada Department of Health and Human Services’ division of public and behavioral health.

Nevada does this by reviewing regular updates from the CDC and “by working with other states to understand the risks of travel-associated cases coming to Nevada,” Vezmar told The Center Square.

“In 2025, there were more measles cases nationally than in any one year since 1992, and so far in 2026 there have been 10 outbreaks in the United States,” he said.

“As transmission continues throughout the country, there is a risk of measles cases occurring in Nevada, highlighting the importance of vaccination and staying away from others during illness to prevent the spread,” Vezmar noted.

Even with no confirmed cases of the measles, Nevada “continuously reviews case data and wastewater testing results to identify potential cases and initiate early response measures,” he said.

Nevada has a vaccination rate of 91%, the CDC said.