Lead
South Carolina reported 20 new measles cases on Tuesday, raising the state’s total for 2024 to 179 and adding momentum to a national outbreak that has exceeded 2,000 cases this year. According to the Centers for Disease Control and Prevention, 93% of U.S. cases were in people who were unvaccinated or had unknown vaccination status. Transmission in the United States has been sustained since about Jan. 20, putting the country close to losing its measles elimination designation unless spread stops within weeks. State officials say transmission in households, schools and churches is ongoing and that 287 people are currently being quarantined.
Key Takeaways
- South Carolina reported 20 additional cases since Friday, bringing its 2024 total to 179 cases, with all but three tied to a Spartanburg County outbreak.
- The U.S. has recorded more than 2,000 measles cases in 2024; 93% were among unvaccinated people or those with unknown vaccination status (CDC).
- Measles transmission in the U.S. has been continuous since roughly Jan. 20; officials warn the country could lose elimination status if spread is not halted within about three weeks.
- State officials have quarantined 287 people in South Carolina and at least three people there have been hospitalized with measles complications.
- Kindergarten two-dose MMR coverage fell below 93% for 2024–25 nationally, down from about 95% in 2019–20; a minimum of 95% coverage is generally cited to prevent sustained spread.
- A large West Texas outbreak accounted for roughly 760 cases from January to August, centered in Gaines County where kindergarten coverage was about 77%.
- Measles exposures have been reported at major transport hubs, including Newark Liberty, Boston Logan and Denver International airports.
Background
Measles was declared eliminated in the United States in 2000, meaning the country had no continuous endemic transmission for a full year. Elimination is maintained when community transmission is interrupted through high population immunity and rapid public-health response to imported cases. In recent years, childhood vaccination coverage has declined in parts of the country and exemptions have increased, eroding the herd immunity that kept measles suppressed.
Before 2024, annual U.S. measles case counts were usually low; this year’s total is the largest since elimination was declared 25 years ago. Localized pockets of low vaccine uptake—often driven by access barriers, misinformation, or philosophical exemptions—have produced the conditions for large outbreaks, notably the West Texas and South Carolina clusters. Public-health authorities now face a mix of pediatric cases, community transmission in congregate settings and travel-related spread that complicates control efforts.
Main Event
South Carolina’s health department announced 20 new cases on Tuesday, raising the state tally to 179 cases for 2024, with the vast majority linked to an outbreak that began in Spartanburg County in northwestern South Carolina. State epidemiologists reported ongoing transmission in households, schools and churches and said 287 people are under quarantine to curb further spread. Officials noted that most cases are among unvaccinated children aged 5 to 17.
Public-health officials in South Carolina and other affected states have attributed part of the rise to recent holiday gatherings, where family events and travel created opportunities for transmission. At least three people in South Carolina required hospitalization for measles complications this year. Meanwhile, other U.S. clusters remain active in Arizona and Utah, and Washoe County, Nevada, reported its first case since 2018 last week.
Nationally, the year’s surge is concentrated in several large local outbreaks. One West Texas cluster centered in Gaines County accounted for approximately 760 cases from January through August and emerged where kindergarten MMR coverage was recorded at about 77%. Health departments have also flagged possible exposures at major airports, increasing the risk that cases could seed new chains of transmission across states and communities.
Analysis & Implications
If U.S. measles transmission remains uninterrupted for a full year since the documented start of sustained spread around Jan. 20, the country could lose its elimination status, a formal designation tied to absence of endemic transmission. Losing that status would be largely symbolic but significant: it would mark a reversal of two and a half decades of public-health progress and could affect international perceptions of U.S. outbreak control and travel guidance.
The epidemiological drivers of this surge are clear: measles is highly contagious, and population immunity has weakened below the roughly 95% threshold recommended to prevent sustained spread. Two doses of MMR are about 97% effective, so gaps in coverage translate quickly into susceptible cohorts, particularly among school-aged children. Areas with single-digit vaccination declines or with localized pockets of low uptake can produce large outbreaks when the virus is introduced.
Policy and communication choices will matter for near-term control. Rapid vaccination campaigns, targeted school- and community-based outreach, and consistent federal messaging supporting MMR uptake are tools that can limit transmission. Conversely, mixed or ambiguous messaging about vaccination and unproven treatments can undermine uptake and delay containment, increasing the likelihood of more cases and hospitalizations.
Comparison & Data
| Location | 2024 Cases (approx.) | Notable vaccination metric |
|---|---|---|
| United States (total) | >2,000 | Kindergarten two-dose MMR <93% (2024–25) |
| South Carolina | 179 | All but three cases linked to Spartanburg outbreak |
| Gaines County, West Texas | ~760 (Jan–Aug) | Kindergarten MMR ~77% |
The table highlights concentrations of cases and the associated coverage gaps. A national kindergarten two-dose MMR rate below 93% represents a reversal from roughly 95% in 2019–20; public-health guidance generally cites at least 95% coverage to sustain herd immunity against measles. The West Texas and Spartanburg clusters show how local dips in coverage can produce large, protracted outbreaks with spillover risk to other jurisdictions.
Reactions & Quotes
“We do anticipate more cases well into January.”
Dr. Linda Bell, South Carolina state epidemiologist (press briefing)
Dr. Bell’s comment accompanied officials’ description of ongoing transmission in homes, schools and churches and the imposition of quarantines to limit spread.
“Vaccines are the best way to prevent the disease. Two doses are about 97% effective and typically offer long-lasting protection.”
Centers for Disease Control and Prevention (CDC)
CDC guidance and state health department messaging have emphasized immunization as the primary tool for interrupting chains of transmission and protecting vulnerable populations.
Unconfirmed
- The degree to which holiday gatherings alone drove the South Carolina spike is plausible but not fully quantified; investigations are ongoing.
- The precise impact of changes in federal vaccine communication on this year’s case totals has not been established; causation remains debated among experts.
- Some reported airport exposures and potential secondary cases are under investigation and may be revised as contact tracing concludes.
Bottom Line
The United States is close to a formal reversal of a public-health milestone: sustained measles transmission since about Jan. 20 risks ending 25 years of elimination status unless spread is rapidly curtailed. The current surge is concentrated in areas with low vaccination coverage and has produced hospitalizations and deaths in unvaccinated people, underscoring the disease’s severity.
Practical steps to reduce risk are well established: increase MMR uptake through clinic-based and community outreach, enforce timely school-entry vaccination requirements where allowed, and maintain clear, evidence-based federal and state messaging. Absent rapid progress in those areas, health departments warn more cases and broader spread are likely in the coming weeks and months.
Sources
- NBC News — reporting on South Carolina outbreak (media)
- Centers for Disease Control and Prevention — measles cases and outbreaks (federal public-health agency)
- South Carolina Department of Health and Environmental Control — measles information and press releases (state health agency)