South Carolina is now experiencing the largest measles outbreak in the United States since the disease was declared eliminated in 2000. As of Tuesday (January 27), health officials have confirmed 789 cases, surpassing last year’s West Texas outbreak, which had 762 cases and resulted in two child deaths.

The outbreak remains centered in Spartanburg County, where health officials say the majority of cases are among unvaccinated children or those whose vaccination status is unknown. The South Carolina Department of Public Health reported 89 new cases since Friday, signaling that the outbreak is not under control and continues to grow rapidly. Quarantines have affected at least 557 people, including hundreds of children at more than 20 schools, who may have been exposed and do not have immunity through vaccination or prior infection.

State health officials have confirmed that at least 18 people, both adults and children, have been hospitalized with complications from measles, though no deaths have occurred in South Carolina so far. The outbreak has also led to cases in North Carolina, Ohio, California, and Washington, which have been linked back to South Carolina.

The Centers for Disease Control and Prevention (CDC) defines a measles outbreak as three or more related cases. Nationwide, the CDC had recorded 416 measles cases this year as of Thursday, before South Carolina’s latest numbers were added. The outbreak in South Carolina alone now accounts for nearly double that figure, and other clusters continue along the Utah-Arizona border.

The majority of those infected in South Carolina have not received the recommended two doses of the measles, mumps, and rubella (MMR) vaccine. According to state data, only 90% of students in Spartanburg County had the required immunizations in the 2024–25 school year, with some schools reporting much lower rates. Public health experts emphasize that a 95% vaccination rate is needed to prevent measles from spreading in a community.

Health officials are urging families to get vaccinated, noting that the MMR vaccine is available at doctors' offices, pharmacies, and local health departments, and is free for many families through programs like Vaccines for Children or health insurance.

Federal agencies, including the U.S. Department of Health and Human Services, are supporting the response with $1.4 million in aid, and the CDC is working closely with South Carolina health officials to track and contain the outbreak.

Measles is a highly contagious virus spread through the air when an infected person breathes, sneezes, or coughs. While most people recover, it can lead to severe complications, especially in unvaccinated children. Health leaders continue to emphasize the critical role of vaccination in preventing further spread.

The WHO Morning News with Jeff Angelo