Measles: Reassessment of the Current Immunization Policy

Abstract

Since the licensure of measles vaccine in the United States a quarter of a century ago, the number of measles cases has declined by 98% to 99%. Since 1981 the number of cases of rubeola reported annually in the United States has averaged about 3000. In 1986, however, 6282 cases were reported, the highest number since 1980, and the incidence was 2.7 cases per 100 000 population, compared with 1.2 the year before. In the subsequent year, 1987, the rate decreased to 1.5 cases per 100 000 population, which was, nevertheless, the second highest rate since 1980. This swell of activity was widespread, with cases reported from 46 states in 1986 and 41 states in 1987. In 1988, the measles activity continued with a rate of 1.3 per 100 000 population. In 1989, the situation worsened, with the Centers for Disease Control having received (as of the end of April) reports of 56 outbreaks which account for more than a 300% increase in cases over the number reported during the similar period of 1988. More than half of cases have occurred in those older than 10 years of age. Among those outbreaks, 32% have been in college students, attending schools in 11 states and involving 71 colleges with at least one suspected case of measles.

Analysis of these recent cases by the Centers for Disease Control has revealed that the majority (about two thirds) were not preventable by our current policy (Figure). In 1985 and 1986 (the most recent years analyzed), most of these nonpreventable cases occurred in persons who either had been appropriately immunized (60%) or in children who were not old enough to receive routine vaccination at 15 months of age (27%) (Table).