Safety and immunogenicity of Haemophilus influenzae type b-polysaccharide diphtheria toxoid conjugate vaccine in infants 9 to 15 months of age.
Sixty 9- to 15-month-old infants were randomly assigned to receive two doses, 1 month apart, of a Haemophilus influenzae type b capsular polysaccharide-diphtheria toxoid conjugate vaccine (PRP-D) or PRP vaccine, each containing 20 micrograms PRP. There were no significant local or systemic reactions. After one dose of PRP-D, 93% of the subjects attained levels of greater than or equal to 0.15 microgram/ml and 59% achieved greater than or equal to 1 microgram/ml antibody protein. These percentages rose to 100% and 86%, respectively, after the second dose, at which time the geometric mean titer of anti-PRP antibody was 4.8 micrograms/ml. IgG anti-PRP levels were 4.3 times higher than IgM. The proportion of IgG to IgM antibody induced by PRP-D increased with age. After two doses, 33% of the PRP recipients responded with a level of greater than or equal to 0.15 microgram/ml and only 19% responded to a level of greater than or equal to 1.0 microgram/ml. One year later, all of the PRP-D recipients tested still had greater than or equal to 0.15 microgram/ml and more than half had greater than or equal to 1.0 microgram/ml antibody protein.
D000907:Antibodies, Bacterial / Q000032:analysis / Q000096:biosynthesis*; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D004168:Diphtheria Toxoid / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D006192:Haemophilus Infections / Q000276:immunology* / Q000517:prevention & control; D006193:Haemophilus influenzae / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007070:Immunoglobulin A / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007223:Infant; D010428:Pentosephosphates / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D010428:Pentosephosphates; D011135:Polysaccharides, Bacterial; C003191:polyribose phosphate