SAFETY AND IMMUNOLOGICAL RESPONSE TO HAEMOPHILUS-INFLUENZAE TYPE-B OLIGOSACCHARIDE-CRM197 CONJUGATE VACCINE IN 1-MONTH-OLD TO 6-MONTH-OLD INFANTS

  • 1 March 1990
    • journal article
    • research article
    • Vol. 85  (3) , 331-337
Abstract
A H. influenzae type b oligosaccharide-CRM197 conjugate (HbOC) vaccine was evaluated for safety and immunogenicity in 432 infants 1 to 6 months of age. In a multicenter study involving 10 sites in six states, infants were vaccinated with three 10-.mu.g doses of HbOC at 2-month intervals. Side effects associated with vaccination were mild, transient, and occurred in fewer than 2% of the subjects. More than 90% of infants of all ages responded after two doses, and more than 98% had anti-H. influenzae type b capsular polysaccharide (HbPs) antibody levels .gtoreq.1 .mu.g/mL after three doses. One month after the third vaccination, the geometric mean anti-HbPs antibody levels were 16.84, 26.23, and 29.11 in infants initially vaccinated at 1 to 2, 3 to 4, and 5 to 6 months of age, respectively. A long-term antibody response was observed; more than 80% of these infants had anti-HbPs levels .gtoreq.1 .mu.g/mL at 2 years of age. the HbOC generated an immune response characteristic of a protein antigen; IgG anti-HbPs antibodies of IgG1 subclass predominated and the response could be boosted. The immune sera killed H. influenzae type b when evaluated in an in vitro bactericidal assay. The data indicate that HbOC safely primed and boosted the immune system of young infants, providing long-lasting protective levels of anti-HbPs antibodies.