A sign outside of Seminole Hospital District offering measles testing, in Seminole, Texas, on Feb. 21, 2025. (Julio Cortez/AP Photo)
Measles cases continue to rise in South Carolina, Utah, and Arizona, as the United States faces its largest outbreak since the contagious disease was declared eliminated in 2000.
The South Carolina Department of Public Health said Tuesday that the state's measles cases have risen to 138 after nine more people tested positive since Dec. 12, following an October outbreak in the Upstate region, including the Greenville and Spartanburg Counties.
As of Dec. 16, 168 people were being quarantined in the state, most of them students from local elementary and middle schools, the department noted.
Utah has reported 21 new measles cases in the past three weeks, bringing the state's total to 125 this year. Arizona's outbreak has been concentrated in the northwest. Mohave County, near the Utah-Arizona border, has recorded 186 cases, with an additional four reported in Navajo County in eastern Arizona.
The surges follow a major measles outbreak in West Texas earlier this year that resulted in 762 confirmed cases since late January. The Texas Department of State Health Services announced on Aug. 18 that the outbreak had ended after causing 99 hospitalizations and two deaths among children.
Public health officials consider a measles outbreak over after 42 days with no new cases because that period is twice the disease’s maximum incubation period, which is the longest time between exposure to the virus and the onset of the illness.
"The end of this outbreak does not mean the threat of measles is over," the Texas Department of State Health Services said.
"Since there are ongoing outbreaks of measles in North America and around the world, it is likely that there will be additional cases of measles this year in Texas. Health care providers should continue to be vigilant and test for measles if their patient has symptoms compatible with the virus."
A measles advisory is displayed on a bulletin board outside the Gaines County Courthouse in Seminole, Texas, on April 9, 2025. Brandon Bell/Getty Images
Measles is a highly contagious respiratory disease caused by the Rubeola virus and is typically spread through the air when an infected person coughs or sneezes.
It is more common in children, and symptoms usually include a high fever, dry cough, runny nose, and a blotchy rash.
According to the Mayo Clinic, a person can spread the virus for four days before the rash appears and for four days after.
Roughly 90 percent of people who haven't had measles or been vaccinated against it will become infected when in the vicinity of someone who has the disease.
Nearly 2,000 confirmed measles cases have been reported across the country this year, resulting in three deaths. This marks the highest number of cases in the United States in more than three decades.
