Now, with 318 cases so far this year, Utah has the second-highest count of measles cases in the country, after South Carolina, which counted 668 infections, according to data from the U.S. Centers for Disease Control and Prevention.

The 559 figure is something Utah hasn’t witnessed in more than 40 years, Dr. Leisha Nolen, the state epidemiologist, said on Thursday. The disease had been practically eliminated thanks to the wide distribution of the measles, mumps and rubella (MMR) vaccine. However, as vaccination rates drop nationwide, measles has appeared in multiple communities across the state.

“Unfortunately, it is a local infection,” Nolen said. “So to even have 20 people infected with measles in Utah would have been shocking and surprising. The fact that now we’re seeing 20 people every week — in fact, probably more like 35 people every week get measles — is amazing and terrifying.”

During the past three weeks, 142 cases have been confirmed among Utah residents, according to state health data, the highest caseload of this outbreak so far, Nolen said.

The concentration of the first measles cases were located in southwest Utah, but sometime in February infections started to spread to other areas of the state. A notable example was reported Wednesday by the TriCounty Health Department, which covers Daggett, Duchesne and Uintah counties. The area confirmed 56 measles infections, up from 23 that were reported last week.

Officials in the area reiterated a message the TriCounty Health Department board issued in 2024.

“We express sincere concern that in recent years the topic of childhood vaccinations has become controversial,” the board wrote. “We encourage honest discussions about the science, history, and health impacts of vaccines. We are confident that the value of vaccinations will be recognized through the health of our residents and/or outbreaks of preventable diseases.”

Since the start of the state outbreak in June 2025, there has been an uptick in the amount of MMR vaccine administration. MMR vaccine administrations have seen a 31% increase in the state compared to the same period the previous year, according to the Utah Department of Health and Human Services. However, that still isn’t enough to combat the spread, Nolen said.

“There’s still a larger number of people out there who haven’t been vaccinated against the measles virus and are at risk of getting this, this pretty bad infection,” she said.

Vaccination among Utah kindergartners during the 2024-2025 school year is 88.6%, according to the CDC, lower than the 92.5% national average, and below the 95% benchmark that guarantees herd immunity.

‘A miserable illness’

State health officials are deeply worried about the severity of the cases that have been recorded in Utah, with many patients experiencing trouble breathing, dehydration, and high fevers.

“Something really concerning to us is this is not a mild infection. We’re seeing around 10% of people having to be in the hospital,” Nolen said. “That’s really extreme.”

About a third of people infected also have needed to go to the emergency room to get care, Nolen said. As of a few weeks ago, three people had been treated in intensive care units.

“It is really a miserable illness. People just really can’t do anything for days. They lose a large amount of weight. Their fevers get up to 105, which is remarkably high. It is. It is really a terrible infection,” she said.

With the spread growing, Nolen encourages people to talk to their doctors about getting the MMR vaccine, which she says about 90% of Utahns have and has proven to be safe.

Still, 56 people infected with measles in Utah during the outbreak had the vaccine, a result of the large exposure to the virus, Nolen said.

“A small percentage of those people are unlucky and get the virus,” she said. “Happily, people who are vaccinated, even if they do get that infection, they do have a milder illness, and they tend to recover much more quickly.”

Nolen also encouraged those who have been exposed to the virus and start to feel sick with a fever, cough, red eyes, runny nose or a rash to call health centers before going in to get care in order to protect others.

A case at the University of Utah

There have been multiple reports of measles exposures linked to large sporting events and other smaller transmission cases. Most recently, the University of Utah sent an alert to students warning them of potential exposure to the virus, with an infected person visiting several spots on campus over multiple days in late March.

That includes the A. Ray Olpin Student Union, and the Empowering Students in STEM conference.

Nicholas Rupp, a spokesperson at the Salt Lake County Health Department, said the school is getting the word out to students who are on record to have been in those spaces at the time. But, since some of the areas are just community gathering spaces, some may not have received the message.

It’s hard to tell how many people have been exposed on campus, but the number may be in the hundreds, Rupp said. Like Nolen, he encouraged Utahns to consider the MMR vaccine since infections can be serious.

“Not everyone will suffer from measles complications. In fact, most people will be just fine getting a measles infection and suffering through it as miserable as it is, and they will survive,” he said. “But not everyone will. We are going to see additional cases, particularly among unvaccinated people, and some of those people are going to have complications.”