Measles Cases in U.S. Double in 2026, With South Carolina and Pennsylvania as Hotspots
New CDC surveillance data show U.S. measles cases through mid-September 2026 have more than doubled from the same period last year, reaching 3,063. South Carolina and Pennsylvania together account for about 44% of the national total, with Pennsylvania reporting 76 of the 101 new cases in the latest week. The surge contrasts with declines in Texas, which led case counts in 2025.
The geographic concentration of cases is striking, with South Carolina, Pennsylvania, and Utah together representing roughly 61% of the national total. The shift from Texas, which dominated 2025 counts, to these new hotspots illustrates how outbreak epicenters can move dramatically between regions in successive years, reflecting changing local conditions.
The NNDSS figures remain provisional and subject to revision as states submit delayed or corrected reports. However, measles' status as a nationally notifiable disease, combined with its distinctive clinical presentation and established outbreak-response procedures, generally yields more complete case ascertainment than for many other reportable conditions, lending reasonable confidence to the overall trajectory.
The concentrated outbreaks could strain local health systems and schools in affected states, particularly where case counts have surged from near zero to hundreds within a year. Families in under-vaccinated communities may face quarantine disruptions, missed work, and healthcare costs. The shifting pattern of hotspots suggests ongoing transmission could continue moving between regions, potentially affecting communities unprepared for large-scale outbreak response and complicating public health planning efforts nationwide.