The effect of reconstitution of an Haemophilus influenzae type b-tetanustoroid conjugate (PRP-T) vaccine on the immune responses to adiphtheria-tetanus-whole cell pertussis (DTwP) vaccine: a five-yearfollow-up

摘要

Controversial results have been obtained from previous studies on the combined administration of Haemophilus influenzae type b-tetanus toroid conjugate (PRP-T) and diphtheria-tetanus-whole-cell pertussis (DTwP) combination vaccines, with regard to possible reciprocal interference between the constituent antigens. To document the priming effect and possible long-term immunogenic interference of PRP-T and DTwP combination vaccines, a randomized, double-blind, controlled study was conducted in Belgium. A total of 168 healthy infants received, at 3, 4 and 5 months of age, DTwP vaccine mixed just prior to injection either with PRP-T vaccine (group A, DTwP//PRP-T, N=85) or with placebo (group B, DTwP//Placebo, N-83), Al the age of 14 months, children of both groups were randomized to receive either a dose of DTwP//PRP-T vaccine (subgroups Al and B1) or a dose of Hib polysaccharide (PRP) vaccine (subgroups A2 and B3). Those children in subgroups Al and B1 had an additional serum sample taken at the age of 5 years (at the time of a DT booster).