Oklahoma notes decline in Haemophilus influenzae: invasive Haemophilus influenzae disease among children aged < 5 years--Oklahoma, 1990-1997.

: Haemophilus influenzae (Hi) causes many clinical illnesses such as meningitis, bacteremia, epiglottitis, pneumonia, otitis media, sinusitis and tracheobronchitis. Before the introduction of the Haemophilus influenzae type b (Hib) conjugate vaccine in 1988, Hib caused more than 95 percent of invasive Hi disease in developed countries. Conjugate vaccines were licensed for use in children > or = 15 months of age in 1989 and for use in children > or = 2 months of age in 1990. During 1987-1995, the incidence of invasive Hi disease among children < 5 years of age decreased 96 percent in the United States. This report summarizes the trend in invasive disease caused by Hi among Oklahoma children < 5 years of age. The data represents cases reported to the OSDH as part of the infectious disease surveillance system. Invasive Hi disease has been reportable by law in Oklahoma since 1983.