CHARACTERIZATION OF THE SERUM ANTIBODY-RESPONSE INDUCED BY HAEMOPHILUS-INFLUENZAE TYPE-B TETANUS PROTEIN-CONJUGATE VACCINE IN INFANTS RECEIVING A DTP-COMBINED VACCINE FROM 2 MONTHS OF AGE

The serum antibody response induced by Haemophilus influenzae type b c apsular polysaccharide (CPS)-tetanus protein conjugate vaccine combine d to DTP vaccine was characterized in infants receiving three injectio ns from 2 months of age. Sixty-five per cent and 94% of infants had an ti-CPS antibody levels greater-than-or-equal-to 1 mug ml-1 after the s econd and third dose, respectively. The antibody response was mostly m ade up of IgG with a marked IgG1 predominance. Significant rises in ba ctericidal and in complement-mediated opsonic activities were observed after immunization. These data clearly show that this vaccine can be successfully administered in one syringe together with DTP vaccine dur ing the regular infant immunization programme.