Randomized trial of the immunogenicity of fractional dose regimens of PRP-T Haemophilus influenzae type b conjugate vaccine.
To assess the immunogenicity of more economical regimens of Haemophilus influenzae type b (Hib) conjugate vaccine, a randomized trial of fractional doses of polyribosylribitol phosphate-tetanus toxoid (PRP-T) Hib vaccine was undertaken in the Dominican Republic. Six hundred children were assigned to one of six regimens with PRP-T vaccine: full-dose, half-dose, and one-third-dose of Hib vaccine given separately or combined with diphtheria, tetanus, and pertussis (DTP) vaccine at ages 2, 4, and 6 months. Regimens that elicited antibody levels > 1.0 microg/mL in >70% of children and < or = 0.15 microg/mL in > 90% of children were considered acceptable. At 1 month post Dose 3, all regimens met the criteria for acceptable response. Among those who received Hib as a separate injection, geometric mean concentrations of anti-PRP bodies (GMCs) at age 1 month post Dose 3 were 11.2, 11.9, and 16.3 in the full, half, and one-third dose groups, respectively. Among those who received Hib and DTP combined, the GMCs were 6.4, 5.2, and 5.7 in the full-, half-, and one-third-dose groups respectively.
Fernández
J
J
Departamento de Enfermedades Infecciosas, Clínica Infantil, Robert Reid Cabral, Santo Domingo, Dominican Republic. infectologia@codetel.net.do
Balter
S
S
Feris
J
J
Gómez
E
E
Garib
Z
Z
Castellanos
P L
PL
Sánchez
J
J
Romero-Steiner
S
S
Levine
O S
OS
D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D018073:Haemophilus Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D006801:Humans; D007223:Infant; D016037:Single-Blind Method; D013745:Tetanus Toxoid / Q000008:administration & dosage* / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; C055753:Haemophilus influenza type b polysaccharide vaccine-tetanus toxin conjugate; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate