Measles vaccine: Record-breaking outbreak may have driven uptake

Key Points:

• South Carolina's measles outbreak, the largest in the US in decades with nearly 1,000 cases and 21 hospitalizations, has officially ended after no new cases were reported for over 42 days, marking two incubation periods without transmission.
• The outbreak, which began in October, contributed to a record year for measles cases nationwide, largely driven by falling vaccination rates; over 90% of cases were among unvaccinated individuals, mostly children.
• Increased MMR vaccination rates, particularly among young children, played a significant role in controlling the outbreak, with a 31% statewide increase in doses administered and a near doubling in Spartanburg County, the outbreak's epicenter.
• Early CDC data indicates a potential national uptick in MMR vaccination coverage among 3-year-olds, rising from 93% in 2024 to 97% in 2025, suggesting a cautious optimism about reversing declining vaccination trends linked to pandemic disruptions and vaccine hesitancy.
• Despite these gains, measles cases continue to rise in other parts of the US with multiple ongoing outbreaks, highlighting the need for sustained public health efforts to maintain vaccination coverage and prevent future outbreaks.