GSTM1 and Hepatitis: Participants received GeneVac-B, a recombinant hepatitis B vaccine, and 0-, 1-, and 2-month schedule anti-HB levels were measured post-vaccination using a commercial enzyme-linked immunosorbent assay (ELISA) kit (AccuDiag ELISA, Diagnostic Automation/Cortez Diagnostics, Inc., USA) to classify vaccine response.