Measles Outbreaks Prompt Widespread Quarantines Across the United States
As measles outbreaks unfold across several states, hundreds of unvaccinated children are being kept from in-person classes and sent into quarantine for a minimum of 21 days. The latest data show 153 students in upstate South Carolina and 118 students in the Minneapolis–St. Paul area isolating after exposure to the highly contagious virus. The evolving situation underscores ongoing questions about vaccination rates, herd immunity, and the capacity of schools to manage outbreaks while continuing to educate students remotely.
Two Hotspots, Two Paths: South Carolina and Minnesota
In South Carolina, a measles case diagnosed in Greenville County signals active, unrecognized community transmission. The virus has been detected in two schools—a K–12 elementary and a charter school—affecting students across multiple grade levels. Health officials emphasize that unvaccinated children exposed to measles must be excluded from school for three weeks to curb further spread.
Meanwhile, Minnesota’s outbreak has led to 118 quarantined students in the Minneapolis–St. Paul metro area after exposure to measles. Public health experts warn that the trend may persist, with infectious disease specialist Michael Osterholm noting that more quarantines could follow as outbreaks continue to unfold.
Why 21 Days? The Isolation Window Explained
The three-week quarantine period reflects the typical window during which measles symptoms can appear after exposure. This precaution helps prevent transmission inside schools and communities, especially where vaccination coverage is imperfect.
Vaccination Rates and the Threat to Herd Immunity
Public health data show that measles vaccination rates in affected areas sometimes fall short of the 95% threshold doctors say is necessary for herd immunity. In Spartanburg County, NBC News data indicate an MMR vaccination rate of 90% for the 2024–25 school year, with Greenville County reporting a similar level. These gaps leave pockets of vulnerability where a measles case can ignite larger outbreaks.
Across the country, vaccination trends have been uneven, contributing to outbreaks that are increasingly driven by local pockets of unvaccinated individuals rather than international travel alone. An NBC News investigation highlighted declines in childhood vaccination rates in many counties since 2019, complicating efforts to maintain measles elimination status.
Broader Outbreak Landscape
Beyond the Carolinas, outbreaks along the Arizona–Utah border have produced one of the largest multistate measles events of 2025, with more than 100 confirmed cases in that region. Utah has also reported additional cases, illustrating how a single vulnerable corridor can seed broader transmission that affects multiple communities and school districts.
Public Health Guidance for Families
Health officials advise families to monitor for fever, rash, and other measles symptoms, which can include high fever, cough, runny nose, red eyes, and characteristic mouth spots before the telltale rash emerges. If exposure is confirmed, students should remain home during the exclusion period and seek medical advice if symptoms develop. Parents are encouraged to review their children’s vaccination records and contact local health departments with questions about eligibility for catch-up immunization.
Implications for Schools and Communities
The combination of outbreaks and variable vaccination rates places strain on schools, which must balance the health of students with educational continuity. Remote learning and remote instruction, already common in the pandemic era, have become critical tools to minimize learning loss while public health officials work to curb transmission. As Dr. Linda Bell, South Carolina’s state epidemiologist, noted, the presence of new cases without a known link points to ongoing community transmission that requires vigilant surveillance and rapid response.
Looking Ahead
As the 2025 season progresses, health experts warn that measles outbreaks could become more frequent if vaccination gaps persist. The United States remains measles-eliminated domestically, but the current trajectory shows that elimination status can be fragile in the face of shifting immunity levels. Continuous vaccination efforts, proactive school-based programs, and clear communication with families will be essential to protecting children and preserving public health gains.
