CDC Deploys ‘Disease Detectives’ as South Carolina Measles Outbreak Nears 1,000 Cases

Federal “disease detectives” have begun fanning out across Spartanburg County, South Carolina, as the state’s measles outbreak climbed toward 1,000 cases—an escalation that has prompted the Centers for Disease Control and Prevention to strengthen its on-the-ground response in the Carolinas.

The deployment was formalized March 9, when the CDC said it was reinforcing the national measles response through closer collaboration with South Carolina and neighboring North Carolina. The move reflects growing concern among public health officials that years of declining childhood vaccination rates are weakening one of the country’s hallmark achievements: keeping measles from spreading widely.

In its statement, the CDC said it is working “hand in hand” with the South Carolina Department of Public Health and the North Carolina Department of Health and Human Services to “contain and prevent measles outbreaks” and to bolster routine immunization.

“Trust is the foundation of public health, earned through openness, honesty, and guided by the best available evidence,” acting CDC Director Jay Bhattacharya said in a video message linked to the announcement. “We are here to offer a wide range of tools, including vaccine supplies, to state and local public health partners.”

What the CDC is sending

The agency said its support includes:

• Epidemiologists from the Epidemic Intelligence Service, commonly known as “disease detectives”
• On-the-ground response teams to assist local health departments
• Advanced laboratory testing and genetic sequencing to track how the virus is spreading
• Outbreak modeling and technical guidance on containment
• Recommendations on vaccination and post-exposure treatment

The CDC also said vaccines are being made available to states upon request to support rapid response.

An outbreak years in the making

South Carolina officials have described the outbreak as “unprecedented.” Measles was first detected in the state’s Upstate region in fall 2025, and an outbreak was declared Oct. 2. Cases accelerated through the winter:

• Jan. 27, 2026: 789 confirmed or probable infections
• Feb. 6: 920
• Feb. 20: 973
• Feb. 27: 985
• March 6: 991

Most infections have been concentrated in and around Spartanburg County, with additional cases reported elsewhere in the state. Health officials have listed exposure sites ranging from churches and schools to big-box stores, skating rinks and a children’s museum.

Children account for the vast majority of patients, with several dozen adult cases. State and federal analyses indicate about 9 in 10 people who became ill were unvaccinated against measles. South Carolina has reported roughly 20 hospitalizations and, so far, no deaths.

South Carolina State Epidemiologist Dr. Linda Bell has repeatedly tied the outbreak’s scale to eroding vaccine coverage.

“Decreasing vaccination coverage is the primary cause of this outbreak and the reason it has reached the scale that it has,” Bell said in an earlier briefing, calling the situation “a milestone that we have reached in a relatively short period of time, very unfortunately.”

Falling vaccination rates and rising exemptions

Declines in vaccination have been gradual but persistent. South Carolina meets the CDC’s measles, mumps and rubella (MMR) coverage target on paper, but only narrowly. State data show that the share of kindergarten students with the recommended two doses of MMR fell from about 95% in 2019–20 to roughly 92% by 2023–24.

At the same time, the number of students claiming religious exemptions from school vaccination requirements more than doubled in five years—from around 12,500 to more than 27,000—meaning about 3% of the state’s schoolchildren attend class without some or all recommended immunizations.

The gaps are wider in certain communities. In Spartanburg County, overall school MMR coverage is closer to 90%. One charter school in the county reported that only about one in five students had received a measles shot in the 2024–25 school year, according to state data cited in multiple news reports. Public health experts say measles typically requires about 95% vaccine coverage in a community to reliably prevent sustained transmission.

National trends point in the same direction. CDC surveillance shows that kindergarten MMR coverage nationwide has fallen from 95.2% in 2019–20 to about 92.5% in 2024–25, leaving hundreds of thousands of children at risk. The proportion of children with formal vaccine exemptions—most of them nonmedical—reached 3% in 2022–23, the highest level since the agency began tracking it.

As those gaps have widened, measles has returned.

The CDC recorded 2,283 confirmed measles cases nationwide in 2025 across 45 states and other jurisdictions, with about 50 discrete outbreaks. As of March 5, the agency had already logged 1,281 confirmed cases this year in 31 jurisdictions, including South Carolina and North Carolina. The South Carolina outbreak accounts for a large share of those infections.

North Carolina on alert

North Carolina’s numbers are smaller but rising. As of Feb. 17, the state reported 22 measles cases since late December, most in unvaccinated people and linked to known outbreaks—including the one in Upstate South Carolina.

Cases have been reported in Buncombe County (including Asheville) and in the fast-growing Charlotte metropolitan area. State officials have published lists of exposure locations and are using local health departments and outreach teams to contact people who may have been exposed.

“Measles is incredibly contagious but also easily preventable,” Dr. Zack Moore, North Carolina’s state epidemiologist, said when the numbers were released. “The increase in measles cases is concerning, especially because it is disproportionately affecting unvaccinated children.”

North Carolina officials have urged all children and adults 1 year and older who are not vaccinated to receive the MMR shot. They have also recommended early vaccination for infants 6 to 11 months old in higher-risk counties, a measure sometimes used during outbreaks.

CDC’s message in a politicized climate

The CDC’s March 9 announcement is also notable for what it says—and does not say—about the politics surrounding vaccines.

The agency’s language on measles vaccination is unequivocal: the MMR vaccine is the best tool to prevent measles and its complications, and serious side effects are “extremely rare.” High coverage, the CDC says, also protects infants, people with weakened immune systems and others who cannot be vaccinated.

The statement arrives during a turbulent period in federal health leadership. The CDC has had multiple directors and acting directors in quick succession. HHS Secretary Robert F. Kennedy Jr., a longtime critic of many vaccines, has pushed changes to the federal childhood immunization schedule, including limiting use of certain combination vaccines and altering which shots are formally recommended for routine use.

Public health organizations and vaccine experts have warned that such changes, along with high-profile skepticism from political leaders, can confuse parents and contribute to declining uptake even when access to vaccines remains intact.

Bhattacharya, a Stanford physician and health economist who has criticized some COVID-19 restrictions, was appointed director of the National Institutes of Health in 2025 and is now also serving as acting head of the CDC. He has publicly endorsed childhood measles vaccination, aligning himself with long-standing CDC recommendations.

“We are working closely with our state and local partners to ensure that communities have the information and resources they need to protect children and families from measles,” he said in the March 9 statement.

Voluntary shots, mandatory quarantines

In South Carolina, the collaboration has focused on support rather than new mandates.

The state has not tightened its religious exemption rules despite the outbreak. Instead, officials have leaned on education campaigns, school exclusion and quarantine orders for exposed, under-vaccinated or unvaccinated students and staff.

At various points in the outbreak, hundreds of children were ordered to stay home from school for weeks at a time after exposures, even if they remained healthy. State health workers have sent mobile clinics to churches and community centers to offer free MMR shots and issued guidance allowing earlier vaccination for infants in affected areas.

Those measures have been designed to respect parental choice while trying to break chains of transmission. They also underscore how individual vaccination decisions can have community-wide consequences, disrupting families who did vaccinate as well as those who did not.

A test of measles elimination—and trust

Measles was declared eliminated in the United States in 2000, meaning it no longer circulated continuously for more than a year and any cases were caused by importations that were quickly contained. Large, prolonged outbreaks such as the one in South Carolina, especially when combined with outbreaks elsewhere, can put that status at risk.

Federal officials and outside experts have warned that if measles continues spreading in under-vaccinated pockets and spilling into other states, the country could lose its elimination designation—a symbolic setback that would also signal deeper problems in the nation’s vaccination system.

For now, CDC officials say their focus is on practical steps: tracing contacts, bolstering local health departments, ensuring vaccine supply and trying to lift immunization rates back above the threshold needed to keep measles in check.

Whether that is enough may depend as much on trust as on shots.

On the ground in the Carolinas, health workers report that some parents who previously declined vaccines are reconsidering after seeing measles up close. Others remain hesitant, citing fears amplified by social media or confusion about shifting national guidance.

Bhattacharya, in his message to state partners this month, acknowledged the challenge.

“Public health depends on the confidence of the people it serves,” he said. “Our goal is to provide clear, evidence-based information so that families can make informed decisions and communities can stay safe from diseases like measles.”

With case counts still climbing in South Carolina and new infections appearing across the border, the coming weeks may show whether that appeal—and the federal response behind it—can contain an outbreak that has already gone further than many health officials imagined.