South Carolina Measles Outbreak

Newsletter written by Science Content Team

Measles Outbreak Accelerating in South Carolina

South Carolina has experienced a rapidly escalating measles outbreak, with more than 200 new cases reported in a single week in mid-January, doubling the total number of cases [1]. Measles is transmitted through the air [2,3], and transmission has been linked to schools and churches, underscoring the high risk of airborne spread in congregate settings.

The outbreak began and stayed concentrated in upstate South Carolina, particularly the Spartanburg area, but cases are spread and have been identified in other parts of the state. 

Transmission linked to the South Carolina outbreak has now also been identified in other states, including North Carolina, California, and Washington. Exposures from travelers from South Carolina have also been reported in Florida, Georgia, and Kentucky [4]. This outbreak is occurring in the context of a 33-year high in measles cases nationally [5].

By the end of January, the outbreak reached almost 847 infected, making it larger than the Texas outbreak last year, and the largest single continuous outbreak since the elimination of measles in 2000 [6]. Although the outbreak has slowed, it has totaled almost 1000 cases. 

Why the Outbreak Is Hard to Contain

Measles is infectious for several days before the characteristic rash appears, which means transmission often occurs before cases are recognized. As a result, reactive measures such as sending exposed children home from school are often implemented too late to prevent further spread.

Vaccination is a critical factor in the spread of measles; in the current outbreak, 93 percent of those infected are unvaccinated or of unknown vaccination status [7].

In addition, measles virus can remain airborne for hours in poorly ventilated indoor spaces. This allows transmission to occur even without close contact, particularly in schools, churches, and other settings where people share indoor air for extended periods.

Schools and Vaccination Gaps

Nearly all identified cases to date have been in people under 20 years of age and due to infections in schools [7]. Of the 950 cases as of Feb. 13th, 246 were in children under 5 and 611 were in children aged 5-17, with only 82 cases in adults 18+ and 11 cases in individuals of unknown age [8]. Young children are particularly susceptible to complications.

Sending exposed children home from school has been used as a quarantine measure, but the extent to which this approach slowed the outbreak is unclear.

Spartanburg County has a high rate of non-medical (for example, religious) vaccine exemptions, which has risen from 3 percent in 2020 to 8 percent currently [9]. This may contribute to the gap between the county’s average school vaccination rate of about 90 percent and the 95 percent coverage needed to prevent measles transmission. Among children under five, vaccination rates in the county are below 75 percent.

Vaccination rates also vary widely between schools. In some affected schools, rates are reported to be as low as 20 percent, meaning that 4 out of every 5 children are susceptible to infection and onward transmission [9,10].  Measles has a very high estimated R0 between 10 and 20 [11], meaning that an average infected person would infect 10-20 other people in a totally susceptible population. Furthermore, schools are especially high-risk environments due to prolonged indoor exposure with dozens of people sharing the same space for hours each day. 

Two doses of the measles vaccine are 97% effective in preventing disease, and symptoms are typically milder even if an infection does occur [12,13]. South Carolina’s public health department has reported that the vast majority of cases in the current outbreak are in unvaccinated people (883 cases, compared to 19 people who were partially vaccinated and 26 people who were fully vaccinated) [8].

Spread Beyond K–12 Settings

As of January 20, the outbreak spread to university settings, with cases reported at both Clemson University and Anderson University [7,14].

A state epidemiologist, Dr. Linda Bell, also reported known exposures and transmission at healthcare facilities, and state health records indicate an exposure incident at a labor and delivery unit; this has been confirmed by South Carolina Department of Public Health internal outbreak reports. Measles is particularly dangerous in babies, who are too young to be vaccinated [4].

Public Health Response

The South Carolina Department of Public Health has encouraged vaccination in response to the current outbreak, and Spartanburg County measles vaccinations in January 2026 more than doubled compared to January 2025 [15]. Public health officials have also been reporting public locations and times where people may have been exposed, and students and schools are also under quarantine.

Following Canada in November and the UK this month [16], the US is also on the verge of losing its measles elimination status. Measles elimination status is based on a chain of transmission spreading uninterrupted for at least a year [17,18].

HHS dismissed concerns about the outbreak in December, predicting that the South Carolina outbreak would not become as large or long-running as last year’s Texas outbreak [18]. That prediction has since proven incorrect. The former director of the CDC’s National Center for Immunization and Respiratory Diseases blames increasing public distrust of vaccines [19].

References

1. Edwards E. “Staring over the edge”: South Carolina measles outbreak doubles in a week. In: NBC News [Internet]. 16 Jan 2026 [cited 9 Feb 2026]. Available: https://www.nbcnews.com/health/health-news/south-carolina-measles-outbreak-cases-double-vaccines-quarantine-rcna253989

2. Riley EC, Murphy G, Riley RL. Airborne spread of measles in a suburban elementary school. Am J Epidemiol. 1978;107: 421–432. doi:10.1093/oxfordjournals.aje.a112560

3. Measles. [cited 9 Feb 2026]. Available: https://www.who.int/news-room/fact-sheets/detail/measles

4. Young A. Maternity unit, BMW plant among groups exposed in South Carolina measles outbreak, records reveal. In: Healthbeat [Internet]. 2 Feb 2026 [cited 9 Feb 2026]. Available: https://www.healthbeat.org/2026/02/02/south-carolina-measles-outbreak-exposure-locations/

5. Benadjaoud Y, Kekatos M, Geho L. New map shows how to spot the measles risk level in your ZIP code. In: ABC News [Internet]. 18 Jan 2026 [cited 9 Feb 2026]. Available: https://abcnews.go.com/Health/new-map-shows-spot-measles-risk-level-zip/story?id=129179712

6. Halpert M. In one South Carolina county, measles starts to feel like next pandemic. BBC. 30 Jan 2026. Available: https://www.bbc.com/news/articles/cwy10l9lwpyo. Accessed 9 Feb 2026.

7. Edwards E, Siemaszko C. First case of measles reported on Clemson University’s campus. In: NBC News [Internet]. 19 Jan 2026 [cited 9 Feb 2026]. Available: https://www.nbcnews.com/health/health-news/measles-clemson-university-rcna254787

8. FRIDAY MEASLES UPDATE: DPH reports 17 new measles cases in Upstate, bringing outbreak total to 950, additional public exposures. [cited 16 Feb 2026]. Available: https://dph.sc.gov/news/friday-measles-update-dph-reports-17-new-measles-cases-upstate-bringing-outbreak-total-950

9. Godoy M. Measles is spreading fast in S.C. Here’s what it says about vaccine exemptions. NPR. 16 Jan 2026. Available: https://www.npr.org/2026/01/16/nx-s1-5677299/measles-outbreak-vaccines-kids-health. Accessed 9 Feb 2026.

10. Farmer T. Despite Upstate measles outbreak, vaccination rates remain low. In: WSPA.com [Internet]. [cited 9 Feb 2026]. Available: https://www.wspa.com/news/measles-spreads-quickly-in-spartanburg-vaccinations-low/

11. Guerra FM, Bolotin S, Lim G, Heffernan J, Deeks SL, Li Y, et al. The basic reproduction number (R0) of measles: a systematic review. Lancet Infect Dis. 2017;17: e420–e428. doi:10.1016/S1473-3099(17)30307-9

12. CDC. Measles vaccine recommendations. In: Measles (Rubeola) [Internet]. 10 Jun 2025 [cited 9 Feb 2026]. Available: https://www.cdc.gov/measles/hcp/vaccine-considerations/index.html

13. What you need to know about measles. [cited 9 Feb 2026]. Available: https://www.who.int/news-room/questions-and-answers/item/what-you-need-to-know-about-measles

14. 2 S.C. universities confirm measles cases on their campuses. In: WRDW-TV/WAGT-TV [Internet]. 17 Jan 2026 [cited 9 Feb 2026]. Available: https://www.wrdw.com/2026/01/17/2-sc-universities-confirm-measles-cases-their-campuses/

15. FRIDAY MEASLES UPDATE: DPH reports 44 new measles cases in Upstate, bringing outbreak total to 920, additional public exposures, and vaccination opportunities. [cited 9 Feb 2026]. Available: https://dph.sc.gov/news/friday-measles-update-dph-reports-44-new-measles-cases-upstate-bringing-outbreak-total-920

16. Triggle N. UK loses measles elimination status. BBC. 26 Jan 2026. Available: https://www.bbc.com/news/articles/cgjw0xegxglo. Accessed 9 Feb 2026.

17. Rosenbluth T, Mandavilli A. One Year After Texas Measles Outbreak Began, Experts Consider Another Grim Milestone. In: The New York Times [Internet]. 19 Jan 2026 [cited 9 Feb 2026]. Available: https://www.nytimes.com/2026/01/19/well/year-anniversary-measles-outbreak-elimination-status.html

18. Shastri D, Associated Press. The U.S. is on the verge of losing its measles elimination status. In: PBS News [Internet]. 20 Jan 2026 [cited 9 Feb 2026]. Available: https://www.pbs.org/newshour/science/the-u-s-is-on-the-verge-of-losing-its-measles-elimination-status

19. Owermohle S, McPhillips D, Tirrell M. Measles elimination status “not really” a concern, CDC official says. CNN. 21 Jan 2026. Available: https://www.cnn.com/2026/01/20/health/cdc-south-carolina-measles-briefing. Accessed 9 Feb 2026.