| Abstract | BACKGROUND: Despite their proven efficacy Haemophilus influenzae type b (Hib) conjugate vaccines are not given to most children in the developing world in the face of an estimated global Hib disease burden of nearly 2 million cases per annum. A major barrier to the introduction of the vaccine would be overcome by diluting the vaccine 10-fold in diphtheria-tetanus-whole cell pertussis (DTP). We report a randomized trial comparing the use of Hib conjugate vaccine diluted in a multidose vial of DTP with that of the full Hib dose. METHODS: We randomized 168 infants to receive either the full dose Hib polysaccharide-tetanus toxoid conjugate (PRP-T) vaccine or a 1/10 dilution prepared by reconstituting the full dose in a 10-dose DTP vial. Infants were vaccinated at 6, 10 and 14 weeks of age and received a full dose as a test of immunologic memory at 9 months of age. Sera were collected at each visit and at 1 week after the booster dose. Serum anti-capsular PRP antibody concentrations were measured by enzyme-linked immunosorbent assay. RESULTS: After the primary vaccination series, 95% of infants in the full dose arm and 94% of infants in the 1/10 dose arm achieved anti-PRP IgG antibody concentrations of > or = 1.0 microg/ml. Infants receiving the diluted vaccine had significantly higher titers of anti-PRP antibody in response to the booster dose (151.36 microg/ml vs. 68.55 microg/ml, P = 0.009). CONCLUSIONS: The 1/10 dose of PRP-T was as immunogenic and safe as the full dose. The technique of diluting a single dose of PRP-T in a 10-dose DTP vial could potentially allow the widespread introduction of Hib vaccine in resource-poor countries currently unable to afford full dose Hib conjugate vaccine. |
| Authors | Mark Nicol, Robin Huebner, Rosalia Mothupi, Helena Käyhty, Nontombi Mbelle, Esther Khomo
(Affiliation: Pneumococcal Diseases Research Unit of the Medical Research Council, South African Institute for Medical Research and University of the Witwatersrand, Johannesburg, South Africa.)
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| Journal | The Pediatric infectious disease journal
(Pediatr Infect Dis J)
Vol. 21
Issue 2
Pg. 138-41
(Feb 2002)
ISSN: 0891-3668 United States |
| PMID | 11840081
(Publication Type: Clinical Trial, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
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| Chemical References |
- Antibodies, Viral
- Bacterial Capsules
- Diphtheria-Tetanus-Pertussis Vaccine
- Haemophilus Vaccines
- Haemophilus influenzae type b polysaccharide vaccine
- Polysaccharides, Bacterial
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| Topics |
- Antibodies, Viral
(analysis)
- Antibody Formation
- Bacterial Capsules
- Developing Countries
- Diphtheria-Tetanus-Pertussis Vaccine
(administration & dosage)
- Dose-Response Relationship, Drug
- Female
- Haemophilus Vaccines
(administration & dosage, adverse effects, immunology)
- Humans
- Infant
- Male
- Polysaccharides, Bacterial
(administration & dosage, adverse effects, immunology)
|
