IMMUNOGENICITY AND REACTOGENICITY OF HBOC VACCINE ADMINISTERED SIMULTANEOUSLY WITH ACELLULAR PERTUSSIS-VACCINE (DTAP) INTO EITHER ARMS OR THIGHS OF INFANTS

To evaluate the reactogenicity and immunogenicity of a Haemophilus inf luenzae type b conjugate vaccine (HbOC) and of a tricomponent acellula r pertussis vaccine (DTaP) when injected simultaneously into either co ntralateral arms or into contralateral thighs, 110 infants were enroll ed to receive three doses of DTaP at 3, 4, and 5 months and two HbOC d oses at 3 and 5 months of age, Administration of either of the two vac cines into arms was associated with significantly more local side effe cts than administration into thighs. There was no difference in geomet ric mean concentration (GR IC) values for any of the four vaccine anti gens between subjects who had been vaccinated into arms or thighs, Aft er immunization, all children had protective antibody titers to diphth eria toxin. While post vaccination the mean anti-tetanus toroid GMC wa s greater than or equal to 1.25 IU/ml, there was no significant rise a s compared to the GMC before vaccination. GMCs of antibodies against t he various pertussis antigens were similar to those observed before wi th the same DTaP vaccine. The simultaneous administration of DTaP and HbOC was safe and immunogenic irrespective of the site of vaccine admi nistration, but significantly more local reactions occurred when vacci nes were injected into arms.