The number of cases of measles has risen in Utah, the state with the most active growing outbreak of the infectious disease, as an outbreak in South Carolina appears to be nearing completion.
The number of measles cases in eastern Utah jumped from 23 to 56 in one week, the TriCounty Health Department said in a statement on April 1.
In Daggett, Duchesne, and Uintah counties, which the health department covers, measles vaccination rates have declined in recent years.
Officials said they understand that people may choose not to receive a measles shot for various reasons, such as religious beliefs and concerns about side effects, but urged people to learn about the benefits of the vaccines as well as the risks.
Officials also said that schools, doctors, and families have been working to reduce the spread of measles.
“Everyone’s working together,” Sydnee Lyons, the public information officer at the TriCounty Health Department, said. “Our community is going above and beyond in terms of … trying to protect not only themselves, but their community members.”
Utah has recorded 362 cases of measles this year through March 31, up from 197 in all of 2025, according to the Utah Department of Health and Human Services. State officials in March said the best way people can protect against measles is to get the measles vaccine, which has an estimated effectiveness of 97 percent after two doses, and also said people should stay home if they have symptoms of measles, such as rash and fever.
Side effects of the vaccine include fever and seizures.
Some vaccinated people have contracted measles in Utah and elsewhere, including doctors, the Utah health department said in a March 16 alert. Fewer than 11 vaccinated doctors have had confirmed measles cases in the state, a spokeswoman for the department told The Epoch Times via email on March 31.
“The vast majority of clinicians in Utah are vaccinated. We are not aware of any unvaccinated clinicians who have developed measles and worked while infectious,” the spokeswoman said. “We do know about some unvaccinated healthcare workers who got measles but did not work while ill. Many of these unvaccinated people live in areas with wide community spread so it’s impossible to identify whether they were exposed in a healthcare setting or in their community.”
Nationwide, some 1,575 measles cases have been confirmed through March 26, according to the Centers for Disease Control and Prevention (CDC). The United States recorded 2,285 cases in 2025, the highest total in a year since 1991.
CDC experts have been assisting states with measles response. A CDC epidemiologist has been working with Utah officials, and other experts have met with state officials on multiple occasions to provide guidance. Additionally, the CDC provided supplemental funding that has helped fund laboratory testing and immunizations, the Utah health spokeswoman said.
The largest outbreak outside of Utah is in South Carolina, where nearly 1,000 people have contracted measles since the fall of 2025. Officials in South Carolina, though, have not identified any new cases for several weeks.
South Carolina officials are waiting until 42 days have elapsed without any new cases to declare an end to the outbreak.
“Forty-two days is the magic number because it is double the number of days for an incubation period, 21 days,” Dr. Brannon Traxler, South Carolina’s new chief medical officer, told reporters in a briefing on April 1. “And so there is a clear indicator if you can get through two incubation periods, of a broken transmission chain.”