DETECTION OF OCCULT HEPATITIS B VIRUS INFECTION AMONG SUBJECTS WITH ISOLATED HEPATITIS B CORE ANTIBODIES: RESULTS FROM A 3-YEAR SURVEY IN AN ITALIAN TERTIARY-CARE HOSPITAL

Background: Hepatitis B virus (HBV) infection causes hepatitis, liver cirrhosis, hepatocellular carcinoma, and death. This study examines the subjects with isolated anti-HBV core antigen antibody (anti-HBcAg), a pattern characterised by the persistent HBV carriage in the absence of HBV surface antigen (HBsAg) and anti-HBsAg antibody. Methods: Based on medical orders, from 2017 to 2019, serological and molecular assays were performed on serum/plasma samples of 33,048 subjects (71.4% Italians, 28.6% foreigners), who referred to the Virology Unit of the University-Hospital of Parma (Northern Italy) for the laboratory diagnosis of HBV infection. Results: The seroprevalence was 4.6% for HBsAg and 11% for anti-HBcAg. The occurrence of the isolated anti-HBcAg status was 3.1%, with higher frequency in males than in females (66.3% vs. 33.7%, P<0.0001), in Italians than in foreigners (54.8% vs. 45.2%, P<0.001), and in outpatients than in inpatients (57.4% vs. 42.6%, P<0.0001). Foreigners with isolated anti-HBcAg came mostly from Africa (67.9%) and Eastern Europe (26.2%). Among subjects with isolated anti-HBcAg, 14.8% had occult HBV infection, 26.3% hepatitis C virus co-infection, 2% human immunodeficiency virus co-infection, and 3.3% both of these latter co-infections. Conclusions: The anti-HBcAg assay accurately evaluates the HBV exposure; subjects with isolated anti-HBcAg antibody should be further analysed for HBV DNA. The HBV infection prevalence in Italy is increasing, due to growing migratory flows from endemic areas.