Comparison of thiomersal-free and thiomersal-containing formulations of a recombinant hepatitis B vaccine (Hepavax-Gene) in healthy adults

Abstract

A thiomersal-free (TF) formulation of the recombinant hepatitis B vaccine Hepavax-Gene has been developed. This study compared immunogenicity and safety of Hepavax-Gene, Hepavax-Gene TF and Engerix-B (containing trace amounts of thiomersal) in a large healthy adult population (N=770) using two vaccination schedules: the priming 0-1-2 months or the standard 0-1-6 month schedule. Hepavax-Gene TF was non-inferior to Hepavax-Gene and Engerix-B with respect to seroprotection rates (>or=10I U/L) 1 month after the third vaccination using the 0-1-6 month schedule, with 99.1% for both Hepavax-Gene formulations and 100% for Engerix-B of subjects' seroprotected in each group. The seroprotection rate after the 0-1-2 schedule was 89.6% for Hepavax-Gene TF, lower than for Hepavax-Gene (94.2%) but comparable to Engerix-B (86.4%). Furthermore, Hepavax-Gene TF was as well tolerated as the comparator vaccines.