South Carolina measles outbreak nears 800 cases, testing U.S. elimination status

The school office at a Spartanburg County elementary building was unusually quiet one recent morning. Desks sat piled with yellow quarantine notices. A handwritten list taped to the receptionist’s window named dozens of students who would not be allowed in class for weeks.

Parents stepped up one by one to hear the same message: Without proof of measles vaccination or documented immunity after exposure, their children had to stay home.

“We hate doing this,” the principal told a mother clutching a kindergartner’s backpack. “But we have to follow the health department’s orders. Measles is spreading in the community.”

That community has become the epicenter of the largest measles outbreak in the United States since the virus was declared eliminated more than two decades ago.

As of Jan. 27, South Carolina’s Department of Public Health reported 789 measles cases linked to an outbreak centered in Spartanburg County, a fast-growing region in the state’s Upstate. Health officials say most of the people who fell ill were not vaccinated.

Across the country, the Centers for Disease Control and Prevention has tallied 588 confirmed measles cases in the first month of 2026, on top of 2,267 cases last year—the highest national total since 1992. Public health agencies warn that if officials cannot quickly rein in clusters like the one in Spartanburg, the United States could lose its measles elimination status for the first time since 2000.

From three cases to hundreds

South Carolina confirmed its first measles case of the current outbreak last summer, an unvaccinated Upstate resident with a history of international travel. By early September, the state had logged three cases.

On Oct. 2, the Department of Public Health declared an official outbreak in the Upstate, citing at least eight confirmed infections, five of them part of a newly identified chain of transmission centered in Spartanburg County.

In the months that followed, the numbers rose steadily. By mid-November, the state reported 52 total measles cases in 2025, 49 of them associated with the Upstate outbreak. Health officials quarantined at least 84 people who had been exposed but lacked immunity.

By Jan. 9, 2026, the outbreak total had climbed to 310 cases. Less than three weeks later, the tally had more than doubled to 789.

“The number of public exposure sites indicates that measles is circulating in the community, increasing the risk of exposure for those who are not immune,” the health department said in an online update of the outbreak.

State data show the virus has reached beyond a single neighborhood or school. Early clusters were linked to a small private school, the Global Academy of South Carolina, and to Fairforest Elementary School, but by winter, more than 30 schools and child care centers had been affected. Exposure locations published by the health department included churches, fitness centers and retail stores in Spartanburg County and surrounding areas.

According to data summarized by the department and outside researchers, 695 of the 789 people infected in the outbreak were unvaccinated. Fourteen had received one dose of measles, mumps and rubella (MMR) vaccine, and 20 had documentation of full vaccination. At least 18 people were hospitalized. No deaths have been reported.

A virus that finds the gaps

Measles is among the most contagious human viruses known. It spreads through the air when an infected person coughs, sneezes or even breathes, and can linger in an enclosed space for up to two hours. One infected person can transmit the virus to as many as 18 others in a susceptible crowd.

Because of that, experts say around 95% of people in a community need to be immune—mostly through vaccination—to prevent sustained spread.

The United States achieved that goal for years. High uptake of two-dose MMR vaccination pushed measles to record lows and led health authorities in 2000 to declare the disease eliminated as an endemic threat within the country. Sporadic cases and small outbreaks still occurred, usually sparked by travel-related infections, but they were quickly contained.

That changed in the past several years. CDC surveys show national kindergarten coverage with two doses of MMR fell from 95.2% in the 2019-20 school year to roughly 92.5% to 92.7% in the 2023-24 and 2024-25 school years. At the same time, the share of kindergarten students with documented exemptions from one or more vaccines rose to 3.6%, the highest recorded.

In South Carolina, state data show kindergarten MMR coverage slipped to 92.1% in 2023-24. Exemptions climbed to 4.5%. Among toddlers 19 to 35 months old, an estimated 88.9% had received at least one dose of MMR.

County-level figures are not all published in a single public dataset, but health officials and outside analysts say Spartanburg has had some of the lowest vaccination rates in the state, with a notably high use of religious exemptions among students.

Measles took advantage of those gaps.

“Measles cases were high in 2025 due to declining vaccination in the U.S. and high measles circulation globally,” said Dr. Nathan Lo, an infectious-disease modeler at the University of California, San Francisco, in an interview earlier this year about the national trend.

State response and a legislative clash

South Carolina law requires children in kindergarten through 12th grade to have two doses of MMR vaccine to attend school, unless they have a medical or religious exemption. Parents seeking a religious exemption must sign a state form in front of a notary and file it with the school.

The same law gives health officials authority to order unvaccinated students out of school when a vaccine-preventable disease is spreading.

“Children who have exemptions may be excluded from school or childcare during an outbreak,” the Department of Public Health advises on its website. The agency says those measures, combined with quarantining exposed contacts, have “made a huge difference in preventing community spread” in some clusters.

During the current outbreak, the department has issued twice-weekly public updates, held media briefings and deployed mobile health units offering free MMR shots in affected areas. County health clinics expanded vaccination appointments. Hundreds of people have been placed under home quarantine after exposure.

At the same time, state lawmakers are debating whether schools should more prominently advertise parents’ ability to opt out of vaccination.

House Bill 4803, introduced in the current legislative session, would require public and private schools and state health agencies to inform parents at least once a year, in writing, that medical and religious exemptions are available. The bill specifies that the notice “must not be presented in a manner that is intended to discourage a parent or guardian” from requesting an exemption.

Supporters have framed the measure as a safeguard for parental rights. Public health advocates warn that normalizing exemptions as a coequal option to vaccination could further erode coverage.

National warnings, mixed messages

The outbreak in Spartanburg is unfolding against a broader national and international backdrop.

After years of low case counts, the United States recorded 2,267 measles cases in 2025 across 49 separate outbreaks. According to CDC summaries, about 89% of those cases were associated with outbreaks rather than single imported infections. Three people died, including two children in Texas and an unvaccinated adult in New Mexico. Roughly 12% of patients were hospitalized.

In an advisory to clinicians in January, the CDC wrote, “In 2025, 12% of reported measles cases in the United States were hospitalized. There were also 3 confirmed deaths from measles.” The agency urged health care providers to “stay alert for measles cases,” especially among unvaccinated patients with recent international travel, and to check MMR vaccination status at routine visits.

The Pan American Health Organization, which certifies whether countries in the Americas have eliminated certain diseases, announced in November that the region had lost its verification as free from endemic measles transmission after Canada reported over a year of continuous spread.

“The Pan American Health Organization announced today that the Region of the Americas has lost its verification as free from endemic measles transmission,” the group said in a November statement.

The same body has called representatives from the United States and Mexico to a virtual meeting on April 13 to review whether those countries still meet the criteria for elimination. To keep that status, nations must show that any outbreaks are limited and that there is no uninterrupted local transmission for at least 12 months.

Federal health experts have raised concerns that the country’s ability to meet that bar is being tested, even as the politics around vaccination shift.

Presidentially appointed leadership at the Department of Health and Human Services and at the Advisory Committee on Immunization Practices, which guides national vaccine recommendations, has drawn attention from public health officials because of past criticism of vaccine mandates and emphasis on personal choice. Some experts say those views risk undercutting CDC campaigns urging families to bring children up to date on shots.

Lives disrupted while the virus spreads

In Spartanburg County, the implications of those larger debates are playing out in everyday routines.

School nurses are tracking exposure lists. Administrators are fielding angry emails from parents whose children, exempt from vaccines for years without consequence, are now barred from classrooms. Other families, with infants too young to be vaccinated or with relatives undergoing cancer treatment, say they are avoiding crowded indoor spaces and watching exposure notices closely.

Local hospitals and clinics have shifted staff to help with contact tracing, vaccination clinics and answering questions from worried patients. Employers are adjusting schedules as workers stay home with quarantined children.

For now, South Carolina officials say there are early signs that aggressive quarantines and vaccination drives may be slowing the outbreak’s acceleration. Case counts are still being updated twice a week.

Whether that will be enough to preserve the United States’ measles-free designation will become clearer in the coming months.

For the second grader at the Spartanburg elementary school, the consequences are immediate. On the first day her class reopened fully after an exposure-related exclusion, she counted empty chairs where several classmates once sat.

“Are they still sick?” she asked her teacher.

The answer was more complicated than she could know: some were ill, some were at home because they lacked a vaccine, and all were now part of a local story with national stakes.