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 3,000. In 1986, however, 6,282 cases were reported, the highest number since 1980, and the incidence rate was 2.7 cases per 100,000 population, compared to 1.2 the year before.1-4 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 wide-spread, 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 (CDC) 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 above 10 years of age. Among those outbreaks, 32% have been in college students attending schools in 11 states, involving 71 colleges with at least one suspected case of measles.
