If you’re feeling sick, it could be measles, Salt Lake County health officials warn

Measles is actively spreading in Salt Lake County.

(Arielle Zionts | KFF Health News) A sign outside a hospital in Rapid City, South Dakota, asks people with measles symptoms to wait outside, because infections are extremely contagious. Scientists are studying measles virus genomes to determine if and how outbreaks around the U.S. this year may be linked.

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Measles is surging in Salt Lake County, and health officials are asking residents to stay home if they’re feeling sick.

“If you have any symptoms of illness at all: stay home, don’t participate in activities,” Salt Lake County health officials said in a news release this week.

So far this year, 28 cases have been confirmed in the county, said Nicholas Rupp, a spokesperson for the Salt Lake County Health Department.

While that number may not seem high, he said, there were only four confirmed cases in all of 2025. Nearly all have occurred in people who have not received the measles, mumps rubella (MMR) vaccine, Rupp said.

The Utah Department of Health and Human Services maintains an online list of known measles exposure sites across the state. There are at least six locations in Salt Lake County, including the Salt Lake City International Airport, Intermountain Christian School and Highland High School.

The case at Highland High, which is part of the Salt Lake City School District, was detected on Tuesday, but the student had been on campus for several days while symptomatic, Rupp said.

District officials immediately began working with the health department to identify students who had been exposed, particularly unvaccinated students, said district spokesperson Yándary Chatwin.

The district, on behalf of the health department, directed those students to quarantine.

“Because of your vaccine exemption status, you must be excluded from school to ensure you are not infected and transmitting measles to others in the community,” the message read. “During this quarantine period, you should not leave home. You should not go to work or be out in the community. You will not be allowed to attend school or school-related activities, including sporting events or extracurricular activities.”

The email noted the quarantine date ends March 6.

Vaccinated students were not required to quarantine but were notified of the exposure.

Measles is highly contagious, Rupp explained, and people often assume they have the common cold or flu — until the “telltale rash appears.”

“You can walk into a room where someone who’s had measles has been in two hours previous,” Rupp said, “and if you’re unvaccinated, you still have a 90% chance of getting measles from that empty room.”

Health officials expect cases will continue to climb.

“We will continue to see measles spread in Salt Lake County, particularly among unvaccinated folks,” Rupp said.

The best protection is the the MMR vaccine, the county news release said.

“Two doses of the MMR vaccine prevent more than 97% of measles infections, and vaccinated people who do still get measles tend to have milder symptoms and are less likely to spread the virus,” the release stated.

Currently, the Centers for Disease Control and Prevention advises adults who were immunized against measles before 1968 to get at least one updated measles shot. That “booster” is for adults who may not recall whether they only received one measles shot before the two-dose regimen was introduced in 1989.

If you think you have been exposed, health officials recommend watching for symptoms for 21 days after exposure.

“The first measles symptoms are often cold- or flu-like, with cough, runny nose, red/watery eyes, and fever, so you may think you have a common respiratory illness and can continue engaging in normal activities,” Dorothy Adams, executive director of Salt Lake County Health Department, said in the news release.

“But please stay home if you have any signs of illness,” she continued, “especially now that we know measles is actively circulating in our community.”