Haemophilus influenzae type B disease, vaccines, and care of exposed individuals.

Before effective vaccines became available, approximately 1 in every 200 children aged younger than 5 years had invasive Haemophilus influenzae type b (Hib) disease. Hib was the most common cause of bacterial meningitis and other invasive bacterial diseases in this age group. Rapid diagnosis and treatment are essential for Hib meningitis, because the mortality rate is 2% to 5%, even with antibiotic treatment--usually a third-generation cephalosporin, such as cefotaxime or ceftriaxone. Because of the use of Hib vaccines, the incidence of invasive H. influenzae disease in children younger than 5 years old declined by 97% between 1987 and 1997. Recent data indicate that the conjugate Hib vaccines given in infancy can be used interchangeably.