2. HIV Group 1 2.1 HIV-1 infection 2.2 ≥18 years old, 2.3 had a CD4+ cell count >200 cells/mm3, 2.4 undetectable plasma HIV-1 RNA, 2.5 were negative for hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc), had no history of previous vaccine, 2.6 were negative for antibody to hepatitis C virus (anti-HCV), 2.7 had no active opportunistic infections (at the time of screening), 2.8 were participated in ClinicalTrials.gov; NCT1289106.and receiving three intramuscular injections of 20 μg of recombinant HBV vaccine (Hepavax-Gene® Berna, Korea) at months 0, 1, and 6 2.9 were willing to sign an informed consent