Occult hepatitis B virus infection in a North American community-based population

Background/Aims Occult hepatitis B virus (HBV) infection [HBV-DNA detection in hepatitis B surface antigen (HBsAg)-negative individuals] may cause acute and/or chronic liver disease. The objective of this study was to document the prevalence of occult HBV in an isolated, North American Inuit community. Methods Four hundred and eighty seven HBsAg negative sera (61% of the community population) were available for HBV-DNA testing by real time PCR. Of these, 80 (Group 1) had serologic evidence of resolved HBV infection and 407 (Group 2) were HBV-seronegative. Results HBV-DNA was detected in 14/80 (18%) and S-variants in 12/14 (86%) samples from Group 1. In Group 2, HBV-DNA was detected in 33/407 (8.1%) and S-variants in 17/33 (52%). In all cases (Groups 1 and 2) viral loads were low (<105 viral copies/ml) and clinical or biochemical features did not distinguish HBV-DNA positive from negative individuals. However, S-variants were more common (P<0.0001) in older age groups. Conclusions The results of this study indicate that in this community-based population; (1) the prevalence of occult HBV infection is 18% in those with serologic evidence of previous HBV infection and 8.1% in HBV seronegative individuals, (2) age, gender and liver biochemistry findings do not identify those with occult HBV and (3) S-variants are present in the majority of individuals with occult HBV.