A new look at measles.

Since the measles vaccine was licensed in the United States in 1963, the number of measles cases has declined by 98%. Nevertheless, measles has not been eliminated as had been hoped, and, in fact, has started to increase in incidence. The increase in the number of cases has been accompanied by a change in measles epidemiology; the highest attack rate now occurs in preschool-age children and in older school-age and college students. The latter is the basis for the adoption of a two-dose measles immunization schedule by the ACIP and AAP. In preschool-age children, however, the problem is more disturbing and reflects low rates of immunization, particularly among inner-city populations. A major public health effort must be directed to achieve and maintain high vaccination rates if measles elimination is to be accomplished. Otherwise, measles outbreaks, with their accompanying morbidity and mortality, will continue to occur.