Epidemiology and prevention of measles.

Measles is a highly contagious viral illness which once affected more than 95% of persons in the United States. Since licensure of a safe and highly effective vaccine, measles incidence has fallen to less than 1% of prevaccination levels. A relative resurgence of measles during 1989-1991, however, focused attention on the need to maintain high immunization levels, particularly among preschool-aged children in urban areas. Improved vaccine coverage levels and a second-dose strategy to eliminate susceptibilities resulting from vaccine failure can help achieve the goal of elimination of indigenous measles from the United States by 1996.