Comparative immunogenicity of two vaccination schedules of a combined hepatitis A and B vaccine in healthy volunteers
Faculty of Medicine and Health Sciences
Journal of viral hepatitis. - Oxford
, p. e5-e10
University of Antwerp
In 1996, a combined vaccine against both hepatitis A and B was licensed and commercialized and has been recommended for healthcare personnel in Belgium. This study compares the immunogenicity against hepatitis B virus (HBV) and safety of two vaccination schedules (0112 months and 016 months) with this vaccine. This is a randomized, stratified and controlled study in healthy adult workers, who are not occupationally exposed to HBV. Seroconversion (≥1 IU/L) and seroprotection (≥10 IU/L) rates were compared using Fishers exact test; geometric mean concentrations (GMCs) of anti-HBs were compared using one-way ANOVA. All statistical analyses were carried out with SPSS 11 on Apple Macintosh. A total of 399 subjects were enrolled in the study, and 356 were analysed according to the protocol. The rate of ≥10 IU/L at 6 months was 70.6% in the group 0112 and 79.9% in the group 016; this rate decreased to 55.9% at 12 months in the first group. Seroconversion and seroprotective rates against HBV measured at month 13 in group 0112 (98.9% and 95.6%) and measured at month 7 in group 016 (99.4% and 97.1%) were not statistically significantly different. GMC of anti-HBs after the 0112 schedule was more than two fold higher than after 016 schedule (P < 0.001). Reported side effects were comparable in both groups with a slight tendency to fewer side effects in the 0112 group after the third dose. The results from our study show that the completed schedule 0112 offers at least equal protective immunogenicity against HBV as the completed 016 schedule. People not receiving their third dose at 6 months can be given this dose up to 12 months after the first dose. The drawback of this flexibility, however, is the longer time period before the protection becomes effective.