South Carolina is facing its largest measles outbreak in over 30 years. State health officials reported on Tuesday, Jan. 27, that the number of confirmed cases has risen to 789.
That total includes 89 new infections identified since the previous update on Friday.
The surge has forced at least 557 people in South Carolina into a mandatory quarantine. This group includes students from several schools who may have been exposed to the virus.
The Centers for Disease Control and Prevention (CDC) has reported 416 cases nationwide so far in 2026. South Carolina’s higher total of 789 includes cases from late 2025, when the state's outbreak first began.
Federal health data shows that most of these cases involve children and teenagers. While many infections are mild, the CDC reports that about 2% of people with measles nationwide have needed hospital care.
Medical experts, including Dr. Kristin Moffitt of Boston Children’s Hospital, say the rise in cases is happening because fewer people are getting vaccinated. The CDC recommends that children receive two doses of the measles-mumps-rubella (MMR) vaccine. According to agency data, getting both doses is 97% effective at preventing measles, while a single dose provides 93% protection.
Vaccination rates among school-aged children have dropped in recent years. For U.S. kindergartners, the vaccination rate fell to 92.5% for the 2024-2025 school year, down from 95.2% five years ago.
