Résumé :
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[BDSP. Notice produite par INIST GUiYR0x9. Diffusion soumise à autorisation]. Background The cost of Haemophilus influenzae type b (Hib) conjugate vaccines has limited their use in non-industrialised countries. To identify more economical vaccination schedules, we carried out a randomised trial of the immunogenicity of alternative regimens to the standard three-dose series. Methods 627 Chilean infants were randomly allocated to one of four regimens with either Hib polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) or Hib oligosaccharide-diphtheria mutant toxoid conjugate vaccine (PRP-CRM197), for a total of eight groups. All infants receive diphtheria-tetanus-pertussis (DTP) vaccine at ages 2,4, and 6 months. The regimens included three full doses, three fractional doses consisting of one half or one third of the full dose, and a regimen of two full doses (at age 4 and 6 months). The primary outcome was the proportion of infants with serum anti-polyribosylribitol phosphate (PRP, the type b capsular polysaccharide) concentrations of 0.15 mug/mL or more at age 8 months. Findings 93% (95% Cl 85-98) of infants vaccinated with three full doses of PRP-T or PRP-CRM197 (95% Cl 84-98) achieved anti-PRP concentrations of 0.15 mug/mL or more at age 8 months, compared with 91% (83-96) to 100% (95-100) of infants immunised with any fractional-dose regimen. Of the infants vaccinated with two doses of PRP-T or PRP-CRM197,99% (93-100) and 87% (77-93) developed anti-PRP concentrations of 0.15 mug/mL or more, respectively. (...)
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