Safety and immunogenicity of Haemophilus influenzae type b-polysaccharide diphtheria toxoid conjugate vaccine in infants 9 to 15 months of age

• Published in: The Journal of pediatrics Vol. 106; no. 2; p. 185
• Main Authors: Lepow, M L, Samuelson, J S, Gordon, L K
• Format: Journal Article
• Language: English
• Published: United States 01-02-1985
• Subjects: Antibodies, Bacterial - analysis; Antibodies, Bacterial - biosynthesis; Bacterial Vaccines - administration & dosage; Bacterial Vaccines - adverse effects; Bacterial Vaccines - immunology; Diphtheria Toxoid - administration & dosage; Diphtheria Toxoid - adverse effects; Diphtheria Toxoid - immunology; Haemophilus Infections - immunology; Haemophilus Infections - prevention & control; Haemophilus influenzae - immunology; Humans; Immunization Schedule; Immunization, Secondary; Immunoglobulin A - analysis; Immunoglobulin M - analysis; Infant; Pentosephosphates - administration & dosage; Pentosephosphates - adverse effects; Pentosephosphates - immunology; Polysaccharides, Bacterial - administration & dosage; Polysaccharides, Bacterial - adverse effects; Polysaccharides, Bacterial - immunology
• ISSN: 0022-3476
• DOI: 10.1016/S0022-3476(85)80284-5

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.