In 1989, recommendations for routine 2nd doses of measles-containing vaccine were issued by both ACIP and the American Academy of Pediatrics (AAP).

During the mid- to late-1980s, a high proportion of reported measles cases were in school-aged children (5-19 years) who had been appropriately vaccinated. These vaccine failures led to national recommendations for a second dose of measles-containing vaccine.

Measles (rubeola) is often a severe disease, frequently complicated by middle ear infection or bronchopneumonia. Encephalitis occurs in approximately one of every 1,000 reported cases; survivors of this complication often have permanent brain damage and mental retardation. Death, usually from respiratory and neurologic causes, occurs in one of every 1,000 reported measles cases. The risk of death is greater for infants and adults than for children and adolescents.