Immunogenicity and safety of high-dose hepatitis B vaccine among drug users: A randomized, open-labeled, blank-controlled trial

Due to the low uptake, adherence, and completion of vaccination among drug users, and their compromised immune responses to hepatitis B vaccination, the current practice of hepatitis B vaccination may not provide optimal protection. The aim of this study was to evaluate the immunogenicity and safety of 60 mu g and 20 mu g hepatitis B vaccines among drug users. A randomized, open-labeled, blank-controlled trial was conducted among drug users at 2 drug rehabilitation centers in China. The eligible participants were drug users who were serologically negative for the hepatitis B surface antigen (HBsAg) and the hepatitis B surface antibody (anti-HBs). Participants were randomized in a ratio of 1:1:1 to receive 20 mu g (IM20 group) or 60 mu g (IM60 group) of hepatitis B vaccine or blank control at months 0, 1, and 6, and followed at months 6, 7, and 12. Seroconversion rates of 94.7% and 92.6% were observed in IM20 and IM60 groups at month 7, and correspondingly decreased to 89.5% and 91.7% respectively at month 12. The IM60 group showed significantly higher geometric mean concentrations (GMCs) of anti-HBs (2022.5 and 676.7 mIU mL-1) than the IM20 group did (909.6 and 470.5 mIU mL-1) at months 7 and 12 (P < 0.05). No safety concerns associated with vaccination were noted. Three-dose intramuscular immunization with hepatitis B vaccines showed good immunogenicity among the drug users.