A measles outbreak, the worst in over two decades, is sweeping the US, with Texas as the epicenter. Over 1,000 cases have been confirmed across 31 states, resulting in three deaths. Health officials are concerned about declining vaccination rates and the potential loss of the nation's measles elimination status,

An infected attendee exposed tens of thousands at a Shakira show last week. Here's how to know if your immunity is up to date-and why adults are being urged to check their vaccine records.