Safety and immunogenicity of subcutaneous H. influenzae vaccines in 15-17 month-old children.
To evaluate the safety and immunogenicity of subcutaneously administered PRP and PRP-D, one hundred and one healthy 15 to 17 month-old children were randomly assigned to receive two subcutaneous doses, 2 months apart, of either vaccine. The incidence of local and systemic reactions did not differ significantly between the two groups. PRP antibody levels in the pre-immunization sera of 95% of subjects were below the level associated with immediate protection from Hib disease (less than 0.15 microgram/ml). After the first dose, 32% of PRP and 70% of PRP-D (p less than 0.001) recipients achieved antibody levels of greater than or equal to 0.15 microgram/ml, and 8% and 26% (p = 0.003) respectively achieved levels greater than or equal to 1 microgram/ml, a level believed to predict long-term protection. After the second dose, antibody levels greater than or equal to 0.15 microgram/ml were reached in 38% of PRP and 88% of PRP-D (p less than 0.001) recipients and levels of greater than or equal to 1 microgram/ml were reached in 22% and 78% respectively (p less than 0.001). The geometric mean levels of PRP antibody after immunization were significantly higher in the PRP-D group after both the first and second doses (p less than 0.001). These results suggest that subcutaneous administration of both vaccines is safe, but PRP-D results in significantly higher antibody levels compared to PRP. The levels were lower than what has been reported following intramuscular administration.
Frayha
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HH
Dept of Pediatrics, McMaster University, Hamilton, Ontario.
Dent
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Shannon
H S
HS
Johnson
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SE
Gordon
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D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines / Q000009:adverse effects / Q000276:immunology; D004168:Diphtheria Toxoid / Q000276:immunology; D005260:Female; D006192:Haemophilus Infections / Q000517:prevention & control*; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007114:Immunization; D007223:Infant; D008297:Male; D010428:Pentosephosphates / Q000276:immunology; D011135:Polysaccharides, Bacterial / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D010428:Pentosephosphates; D011135:Polysaccharides, Bacterial; C003191:polyribose phosphate