Delaware's MMR rate fell below the herd-immunity threshold — then measles returned after a decade

Delaware's kindergarten MMR coverage dropped from 98.5% in 2016 to 94.1%, slipping below the roughly 95% needed for herd immunity. In July, the state recorded its first measles case in over a decade; two days later, officials declared an outbreak of five. Nationally, 2,371 cases reported by July 30 mark a 35-year high.