On Jan. 23, 2015, the U.S. Centers for Disease Control and Prevention (CDC) Health Alert Network issued a health advisory about a multi-state outbreak of measles linked to Disneyland. In Dec. 2015, the U.S. experienced a large multi-state measles outbreak that started in California and pread to six additional states and Mexico. The initial confirmed case-patients reported visiting Disneyland Resort Theme Parks in Orange County, CA, from December 17 through December 20, 2014.