A major measles outbreak in South Carolina has left babies too young for the MMR vaccine especially vulnerable to the disease.
Doctors report that declining vaccination rates have eroded herd immunity, with less than 90% of students vaccinated in the outbreak’s epicentre.
Experts warn that legislative efforts to loosen vaccine requirements could worsen outbreaks, threatening infants and the community’s overall protection.
How did the U.S. go from measles elimination to its worst outbreak in decades?
With infants particularly vulnerable, how are communities protecting those too young for the MMR vaccine?
What specific policy changes are fueling the alarming rise in non-medical vaccine exemptions?
Beyond individual choice, what are the long-term societal costs of eroding herd immunity?
Why are state officials withholding detailed infant hospitalization data during this crisis?
Can 'psychological vaccines' effectively combat the spread of vaccine misinformation?
Measles Resurgence in South Carolina: Nearly 1,000 Cases Linked to Declining Vaccination Rates
Overview
South Carolina experienced its largest measles outbreak since elimination began, with 997 cases concentrated mainly in Spartanburg County where vaccination rates dropped sharply due to rising non-medical exemptions and widespread misinformation. Over 93% of cases were unvaccinated children, leading to severe complications and straining local healthcare. In response, aggressive vaccination campaigns and quarantine measures helped stop new cases by mid-March 2026, with the outbreak expected to end by late April. However, vaccination rates remain below the 95% herd immunity threshold, and ongoing risks from global measles and travel highlight the need for continued efforts to close exemption loopholes, combat misinformation, and maintain high immunization coverage.