OBJECTIVE: To determine the efficacy of recombinant hepatitis B (rHB) vaccine and low-dose hepatitis B immune globulin (HBIG) in the prevention of mother-infant transmission of hepatitis B virus (HBV) infection. METHODS: rHB vaccine was administered to two groups of healthy neonates born to mothers with both hepatitis B surface antigen and e antigen positive in Guangxi, Hunan and Hebei province. Two hundred eighty-nine subjects were included in active immunization group, receiving triple doses of rHB vaccine given i.m. at 0, 1 and 6 month intervals; while 186 subjects receiving 50 IU HBIG at birth with triple doses of rHB vaccine in the low-dose HBIG group. RESULTS: Efficacy of active immunization alone was 87.8% (95% CI: 83.6 - 91.9). Efficacy of rHB vaccine and HBIG was 91.2% (95% CI: 86.7 - 95.6). No significant differences in efficacy by type of rHB vaccine (P = 0.707 2), immunoprophylaxis programs (P = 0.295 5) and regions of living (P = 0.998 7) were noticed. Seroprotection rates (anti-HBs >or= 10 mIU/ml) were detected in 91.1% and 93.5% in rHB vaccine alone recipients and rHB vaccine plus HBIG recipients, with geometric mean titer (GMT) of 153 mIU/ml and 164 mIU/ml at 1 year of age, respectively. Anti-rHBs decreased significantly with years after vaccination (chi(2) = 60.47, P = 0.000 1). Seroprotection rates of anti-rHBs antibodies decreased to 65.0% and 66.6% at 4 years of age in rHB vaccine alone recipients and rHB vaccine plus HBIG recipients, with GMT of 55 mIU/ml and 56 mIU/ml, respectively. CONCLUSION: These results suggested that the effectiveness of rHB vaccine plus low-dose HBIG was much better than only active plasma-derived vaccine; however, methods used for anti-rHBs assay need to be evaluated and verified.