Serological testing for markers of HBV infection was done centrally, as previously described.15 (link) Briefly, HBV-DNA levels were determined using a real-time PCR assay (COBAS AmpliPrep/COBAS TaqMan HBV Test, v2.0; Roche Molecular Diagnostics, Branchburg, NJ). HBV genotype was determined by mass spectrometry at the Molecular Epidemiology and Bioinformatics Laboratory in the Division of Viral Hepatitis at the Centers for Disease Control and Prevention (CDC) with mass spectrometry,16 (link) while quantitative hepatitis B e antigen (HBeAg) and HBsAg levels were measured by Elecsys HBeAg II Quant and Elecsys HBsAg II Quant assays, respectively (Roche Molecular Systems, Inc).17 (link),18 The lowest detectable value for HBV-DNA was 10 IU/mL, for HBeAg was 0.3 IU/mL, and for HBsAg was 0.05 IU/mL; the lowest quantifiable value for HBV-DNA was 20 IU/mL. If not available from the central laboratory, local data were used. Serum biochemical testing including serum aminotransferase and bilirubin levels was performed at local laboratories.