RESUMO
OBJECTIVES: In this open-label, non-randomized phase II study, the safety and immunogenicity of a fully liquid diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HepB-Hib) combination vaccine (Quinvaxem(®)) were assessed in infants who had or had not received a birth dose of hepatitis B (HepB) vaccine. STUDY DESIGN: Two groups of infants, 'HepB at birth' (n=110) and 'no HepB at birth' (n=108), were enrolled and received a primary vaccination course using a 2-4-6 months schedule. RESULTS: Seroprotection/seroconversion rates of >95% were achieved against all antigens included in the combination vaccine for both study groups. Although significantly higher anti-hepatitis B virus (p<0.001) and anti-tetanus (p=0.031) antibody titers were achieved in group 'HepB at birth' when compared with group 'no HepB at birth', the proportion of 'no HepB at birth' subjects achieving protective titers was non-inferior to the proportion of subjects in group 'HepB at birth'. The birth dose of HepB vaccine did not seem to influence the safety pattern of the DTPw-HepB-Hib combination vaccine. CONCLUSIONS: The present study demonstrated that the fully liquid DTPw-HepB-Hib vaccine was safe and immunogenic when administered using a 2-4-6 months immunization schedule, regardless of whether or not infants had received a dose of HepB vaccine at birth.
