Molecular epidemiology and transmission of hepatitis B virus in close family contacts of HBV-related chronic liver disease patients

There is limited data on the patterns of HBV mutation in family contacts of chronic liver disease (CLD) patients in India. DNA sequence analysis is an important tool to study this viral epidemiology. Transmission and prevalence of mutations in the S and pre‐C gene region in HBV infected close family contacts of HBV‐related CLD patients were studied. Twelve HBsAg+ index patients and their 20 HBV DNA contacts were studied in detail. The S ORF and the pre‐C region were sequenced using direct PCR products. S‐gene sequencing included 32 specimens (12 index cases and all 20 contacts). Pre‐C gene sequencing included 26 specimens (12 index cases and all the 14 HBsAg+ contacts irrespective of their HBeAg status). More than 98% sequence homology was found between the index patients and their contacts. The in‐depth study of 12 families revealed that the transmission pattern was primarily horizontal in 6 (50%) and vertical in 2 (17%) families (P