South Carolina measles outbreak declared over

South Carolina health authorities said Monday that the state’s measles outbreak has ended, closing a public health event that lasted nearly six months. Officials reported close to 1,000 confirmed cases and 21 hospitalizations during the outbreak, which began in October. They said the episode also fed into a record annual total for measles cases across the United States.

Officials said the decision to declare the outbreak over followed more than 42 days with no newly reported cases. They described that window as covering two full incubation periods, which they said indicates there is no continuing transmission and that spread has been interrupted. The end-of-outbreak determination was based on the absence of new cases over that specified duration.

State public health leaders largely credited containment to increased vaccination during the response. They said tens of thousands of doses of the measles, mumps, and rubella (MMR) vaccine were administered while the outbreak was active. In Spartanburg County, which officials identified as the outbreak’s epicenter, they said the number of MMR doses given during the response period nearly doubled compared with the previous year.

Across South Carolina, officials reported a 31% year-over-year increase in MMR vaccine administrations, with a particularly notable rise among children under four years old. They linked the state trend to broader national patterns and cited preliminary data from the U.S. Centers for Disease Control and Prevention (CDC). Those preliminary CDC figures show about 97% of 3-year-olds in 2025 had received at least one MMR dose, up from 93% in 2024.

The CDC said the 2025 coverage level is the first time in more than a decade that MMR vaccination rates for 3-year-olds have exceeded the 95% threshold that public health experts view as important for preventing large outbreaks. The agency said the increase likely reflects a shift back toward more typical vaccination patterns after disruptions tied to the COVID-19 pandemic.

From a public policy and market standpoint, the announcement marks the conclusion of an urgent health event that required large-scale vaccination efforts and hospital care for some patients. State and federal vaccination figures were presented as measurable indicators used by health authorities to assess outbreak risk and readiness.

Officials did not release additional details on what initially drove the October outbreak, how cases were distributed beyond the epicenter, or the financial costs of the response.

Authorities also did not say whether any monitoring beyond routine surveillance would follow the declaration. The state’s conclusion, as described by officials, rests on the defined period without new cases rather than on additional operational benchmarks.