Measles is not new, but in 2025 it has made an unexpected resurgence. According to the Centers for Disease Control and Prevention (CDC), the number of confirmed measles cases is now up to 121 since they began tracking on January 1. The outbreak, as it’s being called, is believed to have started with a group of unvaccinated people who visited Disneyland and has since spread to 17 states. Measles is an infectious disease and knowing the facts can keep you and your loved one healthy.