Progress toward eliminating Haemophilus influenzae type b disease among infants and children--United States, 1987-1997.

Haemophilus influenzae type b (Hib) causes serious invasive diseases among previously healthy children aged <5 years. Before the availability of conjugate vaccines in 1988, Hib was the most common cause of bacterial meningitis among preschool-aged children. Since 1993, the incidence of Hib invasive disease (defined as illness clinically compatible with invasive disease such as meningitis or sepsis, with isolation of the bacterium from a normally sterile site) among children aged <5 years has declined >95% in the United States. This report describes the continued decline of reported Hib invasive disease cases and underscores the need for investigation of Haemophilus influenzae (Hi) invasive disease cases.