A measles outbreak in South Carolina, which started in October, shows no signs of abating with the state health department revealing Friday that nearly 100 new cases have been recorded over just the past three days.
In a routine update this afternoon, the health department noted that 99 cases have been identified since Tuesday, pushing the outbreak total to 310 cases. At present, 200 individuals are under quarantine and nine are in isolation. The rapid escalation and numerous exposure sites are making it difficult for health officials to track cases and pinpoint individuals at risk.
“An increasing number of public exposure sites are being identified with likely hundreds more people exposed who are not aware they should be in quarantine if they are not immune to measles,” Dr. Linda Bell, state epidemiologist and the health department’s incident commander for the measles outbreak, stated in the announcement. “Previous measles transmission studies have shown that one measles case can result in up to 20 new infections among unvaccinated contacts.”
The outbreak is primarily concentrated in the northwestern part of the state, notably Spartanburg County. State data indicates that only 90 percent of students in the county were fully vaccinated during the 2024–2025 school year. This is significantly lower than the 95 percent vaccination coverage needed to curb the spread of vaccine-preventable diseases. The county-wide figures likely mask areas with even lower vaccination rates, increasing the likelihood of virus transmission.
Measles is recognized as one of the most contagious diseases, spreading through the air and remaining viable in a room for up to two hours after an infected person has left. When exposed, as many as 90 percent of unvaccinated individuals may contract the virus.