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

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 (≥10 IU/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.