Measles cluster in South Carolina expands, 254 quarantined as cases rise

Health officials in South Carolina reported a sharp increase in measles cases in early December, saying the outbreak that began in October in the Upstate had climbed by 27 new cases since the previous Friday, bringing the local cluster to 111 confirmed infections. State reporting for the year listed 114 cases statewide. More than 250 people, reported by multiple outlets as 254, were under quarantine after possible exposure, and 16 people were in isolation because they were ill.

The new cases were traced to a series of known exposures and household transmission, officials said. Investigators categorized 16 of the newly reported infections as stemming from a prior exposure at the Way of Truth Church in Inman. Eight were household members of known cases, one was linked to a previously reported school exposure, one followed an exposure in a health care setting, and one had no identified source. Public notices identified Inman Intermediate School as a site of exposure, with 43 students placed in quarantine. Students who completed quarantine without becoming ill were scheduled to return to classes on December 15.

State Epidemiologist Dr. Linda Bell told reporters that some people were being quarantined a second time because they had not acquired additional protection through vaccination or prior infection after an earlier exposure. Health departments in Spartanburg County and statewide continued contact tracing, quarantining unvaccinated contacts, and conducting targeted vaccination campaigns in affected communities.

The outbreak has been concentrated among people without prior measles vaccination. State data cited in national reporting indicated that at least 105 of the 111 cases in the Upstate cluster occurred in individuals who had never received a dose of the measles mumps and rubella vaccine. Public health agencies reiterated that two doses of the MMR vaccine in childhood provide about 97 percent protection against measles, and that measles remains one of the most contagious infectious diseases, able to linger in the air for hours after an infected person leaves a room.

Officials are applying a standard 21 day quarantine period after exposure, reflecting the virus incubation window. Some students are serving a second 21 day quarantine following repeated exposures this school year, a disruption that has cascading impacts on families, workplaces, and classroom instruction.

The South Carolina cluster is one of several sizable outbreaks nationwide, with locally reported large outbreaks in Utah and Arizona at roughly 115 and 176 cases respectively, and the Centers for Disease Control and Prevention reporting more than 1,900 measles cases in the United States this year. Public health leaders warned that sustained transmission through January could mark 12 consecutive months of circulation and end the nation s measles elimination status first declared in 2000.

Beyond immediate containment measures, the outbreak underscores persistent gaps in vaccine acceptance and access. Public health experts say addressing misinformation, improving access to vaccination in underserved communities, and supporting schools and congregations for rapid response are critical to stemming spread and protecting those most vulnerable. Health departments said more cases were likely in the coming weeks and advised communities to confirm vaccination status and seek MMR immunization where needed.