South Carolina Department of Public Health officials declared the state's measles outbreak over on Monday. The Upstate-concentrated outbreak ended after nearly 1,000 people were infected with the disease in seven of the state's counties.
Officially declared Oct. 2, the outbreak grew into the largest in the nation since the disease was declared eliminated in 2000. Children were the main group infected; of the 997 total cases, 903 were in children ages 17 and younger. The outbreak spread through schools, churches and within households.
DPH held its final outbreak media briefing Monday. In the briefing, agency Chief Medical Officer Dr. Brannon Traxler said children were the most vulnerable group in "the sense of not having immunity." She said older populations tended to either have been exposed naturally as children or been vaccinated.
Growing vaccine hesitancy and declining school immunization rates bloomed into the spread in children. Schools in the Upstate have seen the most consistent drop in the percentage of students with required immunizations within the last five school years, according to DPH public data.
In the 2021-2022 public school year, 95.5% of students in Upstate schools had required immunizations. So far through the 2025-2026 public school year, 92.2% of students in the Upstate have required immunizations. At least 94% of students in each of the Midlands, Lowcountry and Pee Dee regions have their required immunizations.
Traxler said, too, that the spread could be partially reflective of the way children ages 5-17 congregate on such a consistent basis.
"That's the age that kids are out and about and interacting with each other," she said.
Still, children in the state were infected at a higher rate than national averages.
DPH and the Centers for Disease Control and Prevention publicly disclose case numbers in different age ranges. Of the 990 state outbreak cases with a known age, 87, or 8.79%, were in people aged 18 and older.
The CDC groups its 18- and-19-year-olds with children in its public case reports. The federal agency reports its adult measles cases beginning at age 20. In 2025, 30% of measles cases nationwide were in adults. It is a difference of about 21 percentage points.
Thirty-three schools were impacted with exposure, and a total of 874 students were asked to quarantine. Quarantine at times lasted through holidays like Christmas and Hanukkah.
DPH has said a strong increase in state vaccination numbers were key in the eventual plateau of case spread. Compared to the same months in the previous year, 19,243 additional vaccine doses were administered in the state from October 2025 through March.
The agency equipped mobile health units to administer doses of the measles, mumps and rubella vaccine. By March, just 76 doses had been administered in the units, which typically offered vaccinations on weekdays during working hours.
Public exposures ranged from local restaurants to gyms. And although exposure was reported in Columbia, no cases were reported in Richland or Lexington Counties. People who live in Spartanburg County made up the majority of reported cases.
People in Greenville County, Anderson County, Pickens County, Lancaster County, Cherokee County and Sumter County also contracted the disease.
DPH said the outbreak cost the state about $2.1 million. The agency will now move into a more typical measles monitoring routine as staff from other departments move back into their original roles.
Sunday was the official final day of the outbreak, as a 42-day period of days with no new outbreak-related cases was needed before the outbreak could end. DPH last confirmed a case in mid-March.
DPH Interim Director Dr. Edward Simmer said in a statement that the department will remain vigilant in its monitoring. He called the MMR vaccine the best way to prevent measles. Of cases with a known vaccination status, 94% were in fully unvaccinated people.
