The immunological response of thai infants to Haemophilus influenzae type B polysaccharide-tetanus conjugate vaccine co-administered in the same syringe with locally produced diphtheria-tetanus-pertussis vaccine

Objective: Comparing the immunogenicity and reactogenicity of three vaccine combinations. These were GlaxoSmithKline Biologicals' (GSK) Haemophilus influenzae type b vaccine (Hib-TT; Hiberix™) administered with the local Government Pharmaceutical Organization's (GPO) diphtheria-tetanus-pertussis whole cell (DTPw) vaccine, Hib-TT mixed with GPO's DTPw vaccine, or Hib -TT mixed with GSKs' DTPw vaccine (Tritanrix™. Material and Method: An open, randomized, controlled, single center study of three hundred and sixty infants. They were randomized into three groups to receive either Hib-TT; Hiberix™ mix with GPOs' DTPw vaccine (group 1), Hib-TT mixed with GPO's DTPw vaccine (group 2), or Hib -TT mixed with GSKs' DTPw vaccine (Tritanrix™; group 3) at two, four and six months of age. Result: One month after the third dose, all subjects had antibodies level against Hib polyribosylribitol phosphate (PRP) ≥ 0.15 μg/ml. All subjects except two (in group 2) had anti-PRP levels ≥ 1.0 μg/ml. The geometric mean concentrations were similar in all three groups. Over 96% of the subjects in all three groups demonstrated an immunological response to diphtheria, tetanus, and pertussis antigens. There was no difference among the three groups in terms of severe local reaction and fever. Conclusion: The present study showed that the combined vaccines produced an effective antibody response with no increase in reactogenicity compared to separately administrated vaccines.