Dropping vaccine mandate could spark the largest measles epidemic in the United States – News-Medical

Dropping vaccine mandate could spark the largest measles epidemic in the United States  News-Medical

Measles is making a comeback. Once considered eliminated from the United States, the disease has been popping up around the country as vaccine coverage declines. Now, as Florida considers dropping its measles, mumps and rubella (MMR) vaccine mandate for school attendance, a new University of Maryland study predicts that such a policy change could spark the largest measles epidemic in the United States in nearly 500 years. The study will be published in the Proceedings of the National Academy of Sciences on September 28, 2026. Measles is one of the most contagious human pathogens, and we've seen a striking 650% increase in cases just between 2024 and 2025. This is an extremely important case study with ramifications well beyond the southeastern United States." Abba Gumel, paper co-author, a Distinguished University Professor of Mathematics at UMD As vaccine hesitancy and exemptions grow, 3,471 measles cases have been confirmed nationally so far this year-reaching 45 states plus Washington, D.C., and New York City.

Recent infection clusters in Texas, New Mexico and South Carolina arose as these states fell below their respective vaccine-induced herd immunity thresholds-the minimum percentage of a population that must be vaccinated to stop the person-to-person spread of a disease. To assess potential outcomes of Florida's proposed vaccine-mandate retraction, the UMD team built a transmission model based on a 2025