A new study warns that removing Florida’s school-entry vaccination requirement could lead to one of the worst measles epidemics in US history, as declining immunisation rates leave tens of thousands of children vulnerable amid a nationwide resurgence.
Florida’s debate over school vaccination rules has arrived at a moment when measles is already surging back across the United States. According to the Centres for Disease Control and Prevention, there have been 3,471 confirmed cases so far this year, spread across 45 states plus Washington, D.C. and New York City. The CDC says falling MMR coverage among kindergartners is leaving tens of thousands of children vulnerable, while a University of Maryland study warns that removing Florida’s school-entry requirement could help turn that weakness into a far larger outbreak.
The University of Maryland team modelled what could happen if Florida dropped its measles, mumps and rubella mandate, using a 2025 outbreak in Gaines County, Texas, as a starting point and adding Florida’s population patterns, vaccination rates and age-based mixing. Their findings, set out in a paper due in the Proceedings of the National Academy of Sciences, suggest the state is already below the herd-immunity threshold needed to stop sustained spread. The researchers say further declines in childhood vaccination could drive a large epidemic and, in the worst case, deaths on a scale not seen in the pre-vaccine era.
Abba Gumel, a co-author of the study, said measles is one of the most contagious human diseases and noted that cases have risen sharply in recent years. Alice Oveson, the study’s lead author, said vaccinating children has a much larger effect on slowing transmission than vaccinating adults because children tend to mix more closely in schools and other settings. She compared the risk to a forest full of dry kindling, arguing that even modest drops in childhood uptake can produce outsized outbreaks.
The warning lands as public-health officials face a broader deterioration in protection against a disease once declared eliminated in the United States. The CDC says kindergartner MMR coverage has fallen from 95.2% in the 2019-20 school year to 92.4% in 2025-26, leaving about 280,000 children at risk. The Council on Foreign Relations and The Atlantic have both described a wider resurgence that has already pushed the country towards the edge of losing its elimination status, with 2025 marking the worst year for measles in decades and 2026 continuing to bring new transmission. The Maryland researchers argue that catch-up vaccination in adults and temporary measures such as masking and isolation can help during outbreaks, but not replace the protection that school vaccination mandates have historically provided.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
