In December, South Carolina's measles case reports appeared to be declining. A modeling tool inside the Centers for Disease Control and Prevention said the opposite, and the state kept its response staffing high through the holidays partly as a result. Within two weeks, cumulative confirmed cases more than doubled.
That sequence is the centerpiece of a CDC report published August 27 in the agency's Morbidity and Mortality Weekly Report, evaluating how a technique called nowcasting performed during the largest measles outbreak in the United States in roughly three decades. The outbreak ran from October 2025 through March 2026 and ended with 997 cases, a figure the report attributes to the South Carolina Department of Public Health.
