A significant and highly contagious measles outbreak is escalating across South Carolina, with health officials reporting hundreds of confirmed cases as the state becomes a focal point for the disease's resurgence in the United States.
University Case and Statewide Surge
Clemson University, home to nearly 30,000 students, announced on Saturday that an individual affiliated with the institution had a confirmed case of measles. The person is now isolating in line with state health guidelines. The South Carolina Department of Health is conducting contact tracing and notifying those potentially exposed via email.
The university stated that nearly 98 percent of its students have provided proof of measles immunity, typically through the two-dose MMR (measles, mumps, and rubella) vaccine. For the fully vaccinated, the risk of infection is just three percent, with usually milder symptoms. However, an unvaccinated person has a 90 percent chance of infection from brief exposure to the airborne virus.
This case is part of a much larger outbreak. According to the latest CDC data, South Carolina has recorded 145 cases since the start of 2026. More strikingly, state figures show 558 cases have been reported since October 2025. As of recent updates, 531 people are in quarantine and 85 are in isolation across the state.
Vaccination Rates and Herd Immunity Breached
The outbreak's severity is closely linked to suboptimal vaccination coverage. State data reveals that only 91 percent of kindergarteners have received both MMR doses, falling below the 95 percent threshold required for herd immunity. In some schools, vaccination rates are as low as 20 percent.
An analysis of the 558 cases since October 2025 shows the impact on the unvaccinated is stark: 483 individuals had not received any MMR vaccine. Only 13 were fully vaccinated, while six had one dose and 56 had an unknown status. The vast majority of cases (372) were in children aged five to 17, with 134 in children under five.
The outbreak has been largely centred on Spartanburg County, on the border with North Carolina. Health alerts have been issued for locations visited by infected individuals, including the South Carolina State Museum in Columbia, and a Walmart, Wash Depot laundromat, and Bintime discount store in Spartanburg.
National Context and Serious Health Risks
This surge in South Carolina is part of a wider national trend following a record-breaking outbreak last year. Cases have also been reported in 2026 in Florida, Georgia, North Carolina, Ohio, Arizona, Utah, Oregon, and Washington state. In one instance, the Snohomish County Health Department in Washington confirmed three measles cases in children exposed to a contagious family visiting from South Carolina.
Measles, declared eliminated in the US in 2000, is a serious disease. It causes flu-like symptoms and a distinctive rash, and can lead to severe complications including pneumonia, seizures, and brain inflammation. While rare, brain swelling from measles is deadly in 15-20% of cases and can cause permanent neurological damage. The virus also severely weakens the immune system, leaving patients vulnerable to other infections.
The two-dose MMR vaccine, given at 12-15 months and again at 4-6 years, is 97 percent effective at preventing measles. The World Health Organization estimates measles vaccination prevented 60 million deaths globally between 2000 and 2023. Health officials urge vaccination as the only sure defence against the ongoing outbreak.
