Salt Lake County has its first confirmed measles case, health officials say

The case is “especially concerning,” the head of the Salt Lake County Health Department said, because the source of the unvaccinated person’s infection is unknown.

(Centers for Disease Control and Prevention) An example of a measles virus.

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Officials with the Salt Lake County Health Department have confirmed the county’s first measles case during the current national outbreak — and officials can’t say where the patient caught it, according to a news release Friday.

Gabriel Moreno, a spokesperson for the health department, said officials first learned of the case Wednesday afternoon, when they received positive lab results showing an unvaccinated adult was infected with the disease.

Wednesday evening and throughout Thursday, Moreno said the department investigated the case and interviewed the patient.

Despite those efforts, health officials said they weren’t able to figure out how the person caught the virus, according to the news release.

“This case is especially concerning because the source of the patient’s infection is unknown,” said Dorothy Adams, the health department’s executive director. “They have not knowingly had contact with anyone who had measles, which means their infection is the result of transmission somewhere out in the community.”

The person may have exposed others to the measles at Intermountain Health’s Taylorsville InstaCare at 3845 W. 4700 South in Taylorsville last Friday, Nov. 7, between 3-7:15 p.m., according to the news release.

Moreno said officials have made contact with most, if not all, of the individuals they know of who were exposed in the urgent care lobby.

Measles can linger in the air for up to two hours after an infected person leaves an area, according to the Salt Lake County Health Department. Because of this, officials advise anyone who was at the Taylorsville InstaCare during that time period to check their MMR (measles-mumps-rubella) vaccination status.

If people have received one or two doses of the MMR vaccine, they are considered immune, according to the health department. After receiving two vaccines, officials say people are protected from measles infections 97% of the time.

The measles case in Salt Lake City is the 77th confirmed in Utah this year, and the 13th confirmed in the state within the last three weeks.

In late October, Salt Lake County health officials believed a different person was infected, but said that person refused to be tested or take part in an investigation. Without those results, officials said they could not confirm the case.

That unconfirmed case is not related to the case confirmed this week, officials said.

Throughout the United States, health officials have confirmed 1,700 cases confirmed by 42 states, according to the Centers for Disease Control and Prevention.

The national outbreak comes as fewer kindergartners are receiving the MMR vaccine, the CDC has reported. If more than 95% of a community is vaccinated, the CDC says they can achieve “herd immunity.” However, the agency reports, kindergartners’ vaccination rates nationwide dropped from 95.2% in the 2019-20 school year to 92.7% in 2023-24.

Numbers stray even further from herd immunity in Utah, where the CDC estimates only 88.8% of kindergartners were adequately vaccinated against measles during the 2023-24 school year.