On May 18, 2006, the U.S. Centers for Disease Control and Prevention (CDC) resported on a multi-state mumps outbreak with over 6,500 cases, which affected a number of college-aged students in the Midwest. In the U.S., the reported incidence of mumps declined after introduction of mumps vaccine in 1967 and the recommendation for its routine use in 1977.

To prevent mumps, the Advisory Committee on Immunization Practices recommended a 2-dose MMR vaccination series for all children, with the first dose administered at ages 12–15 months and the second dose at ages 4–6 years. Two doses of MMR vaccine were recommended for school and college entry unless the student had other evidence of immunity.