Most patients treated at Prisma Health Greenville Memorial Hospital during South Carolina’s recent measles outbreak were children 10 or younger, and at least 73% were unvaccinated, the health system’s physicians reported.
In a research letter published in The New England Journal of Medicine, clinicians at the Greenville, S.C.-based system said they treated 81 people for measles from October 2025 to April 2026. The state’s outbreak, the largest in the U.S. in more than 35 years, totaled 997 cases.
Most infections were concentrated in the Upstate region and Spartanburg County, where measles, mumps and rubella vaccination coverage was 88.9%. Statewide, 93% of cases were among unvaccinated residents, according to the research letter.
None of the 81 patients died. Ten children and three adults were hospitalized, mostly for dehydration, respiratory problems or pneumonia, and most went home within 72 hours. During the height of the state’s outbreak, ProPublica reported that South Carolina measles admissions were “vastly underreported” because the state did not require hospitals to log them.
Two patients had prolonged stays with measles encephalitis, a life-threatening inflammation of the brain. One was discharged to an inpatient rehabilitation facility and remains in outpatient therapy; the other recovered but still has headaches and a vocal tic.
The report also documents measles’ longer tail. Within a month of diagnosis, 24 patients developed concurrent or subsequent infections — most commonly pneumonia, ear infections and sinusitis — a reminder of the immune suppression measles can leave behind. Koplik spots, the bluish-white lesions inside the mouth that are a hallmark of the disease, appeared in one-fourth of patients.
The account offers a rare operational look at how one system absorbed a measles surge as U.S. cases climb toward last year’s total. As of July 16, the CDC has confirmed 2,260 measles cases; in 2025, the agency confirmed 2,289 cases.
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