Abstract
Vaccination with recombinant hepatitis B vaccines is highly effective in preventing hepatitis B infection. Recently, a preservative‐free (PF) formulation of hepatitis B vaccine [GlaxoSmithKline (GSK) Biologicals, Rixensart, Belgium] has been licensed. The immunogenicity of the PF hepatitis B vaccine and antibody persistence 6 years later was assessed in this study. This formulation was compared with the preservative‐ containing (PC) formulation of the vaccine and a low‐preservative (LP) content formulation. Five hundred forty‐one healthy adult subjects were evaluated in the primary study. Over 94% of the subjects in the three study groups had seroprotective anti‐HBs antibody concentrations (≥10 mIU/ml) 1 month after completing primary vaccination. Antibody measurements in 242 healthy adults who returned for the follow‐up study and who had received primary vaccination 6 years earlier showed that over 81% of subjects in the three study groups still had anti‐HBs antibody concentrations ≥10 mIU/ml. No apparent differences in antibody decline or distribution between the study groups were observed. These results indicate that the removal of preservatives from the hepatitis B vaccine does not affect adversely its immunogenicity both in the short and in the longer term. J. Med. Virol. 81:1710–1715, 2009. © 2009 Wiley‐Liss, Inc.