Efficacy of post liver transplant hepatitis B booster vaccination in chronic hepatitis B recipients with prior immune response

Abstract

BACKGROUND: Previous study has shown that the presence of anti-HBs in HBV recipients after LT in the absence of HBIG and use of Pre-S containing HBV vaccine (Sci-B-VacTM), induced immune response in half of the patients. This study aims to determine the efficacy of booster vaccine in selected patients after LT. METHOD: Patients who had LT for HBV with either; group 1) previous immune response from vaccination; 2) detected anti-HBs for >1 year after LT or 3) peak anti-HBs >100 IU/ml. All received intramuscular injection of double dose Sci-B-VacTM. The primary end point was production of anti-HBs>10 IU/L (from previous negative value) or 2-fold increase from baseline was considered positive response. HBV serologies & HBV specific immune responses were taken at baseline, day 14, month 1,2,3,4,5 & 6 afterwards. RESULTS: 86 patients were recruited and 21 (24.4%) had responded. All five patients in group 1 responded, 7/45 (15.6%) in group 2 and 9/36 (25%) in group 3 responded (p<0.001). .Serial changes in anti-HBs in responders was shown in Figure 1. Responder and non-responder were the same in terms of age, sex, blood group, type of LT and indication. Production of anti-HBs was also independent of e antigen status and HBV DNA level before LT but non-responders were more likely to have HBV mutant(21.5 vs. 0%, p=0.04).Responders had significantly higher peak anti-HBs before booster (193 vs. 29 IU/ ml, p=0.011) and were less likely to have anti-HBs loss (57.1 vs. 81.5%, p=0.024).Univariate analysis showed that anti-HBs loss and peak anti-HBs before booster vaccination, age of recipients and HBV immune donors were significant predictors while peak anti-HBs level before booster vaccination was the only significant predictors on multivariate analysis. CONCLUSION: HBV vaccine has limited efficacy in patients after LT. Further studies are needed to identify who would benefit most from active immunization and to increase response rate.