A Randomized, Prospective Field Trial of a Conjugate Vaccine in the Protection of Infants and Young Children against Invasive Haemophilus influenzae Type b Disease

THE importance of Haemophilus influenzae type b bacteria as the primary cause of bacteremic infections in children has been realized only recently. In the United States, 85 percent of the approximately 20,000 cases of invasive H. influenzae type b infection occurring each year are found in children younger than 5 years of age, with a peak annual incidence of 275 per 100,000 among infants 6 to 11 months old. 1 A capsular polysaccharide vaccine proved efficacious in preventing invasive H. influenzae type b disease in children who were 18 months of age or older in a prospective, randomized, double-blind trial conducted . . .