Combination infant vaccines which reduce the number of separate injections, and which simplify schedules are needed to improve uptake. Recent attempts to combine DTP, Hib, and hepatitis B vaccines have been hindered by inadequate seroresponse to component antigens. We have piloted a new pentavalent vaccine in a 2, 4, and 6 month primary course immunisation schedule. This vaccine incorporates an Australian whole-cell pertussis based DPT vaccine (30Lf diphtheria toxoid, 6Lf tetanus toxoid, ≤20×109 inactivated Bordetella pertussis: CSL Ltd), 7.5mcg liquid PRP-OMP conjugate Hib vaccine(Merck & Co.), and 5mcg HBsAg recombinant hepatitis B vaccine (Merck & Co.). In an open community study, 45 healthy infants aged 2 months were recruited through health centres. One month post-dose serology(Table) is being carried out. Parents completed sign/symptom diaries. There were no serious adverse events. The minor adverse reaction profile was similar to DTPw vaccine. Pertussis antibodies (GMT units/mL) were (d2, d3): PTX 1.2, 6.5; FHA 9.2, 26.8; Pertactin 1.6, 14.5; Agg2 8.0, 39.5; Agg3 11.0, 73.0. This vaccine appears to induce a satisfactory seroresponse for all components, and to have an acceptable reactogenicity profile. Further detailed evaluation is underway.

Table 1
Full size table