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We read with interest the article by Bakr et al (GUT 2006;55:1183‐7). The authors recruited 4720 residents aged 18–65 years from a rural community in Egypt, a country hyperendemic for hepatitis C virus (HCV) infection, which might be attributed to mass campaigns for intravenous antischistosomal treatment.1 They found that the HCV antibody (anti‐HCV) was positive in 910 individuals (19.3%), and 38.5% of the anti‐HCV‐positive individuals were negative for serum HCV RNA. Interestingly, the authors concluded that women had a significantly higher HCV clearance rate (44.6% vs 33.7%, respectively; p=0.001, adjusted OR 1.77) than men, which was similar to reports by Inoue et al2 and Yamakawa et al3 from Japan.
We conducted a large‐scale community‐based study in southern Taiwan, a country hyperendemic for hepatitis B virus (HBV) infection (prevalence of hepatitis B surface antigen (HBsAg) 10–20%), and several villages were reported to be hyperendemic for anti‐HCV (prevalence of anti‐HCV 17–50%).4,5,6 Among the general population of the Kaohsiung area aged 40–65 years, 11239 subjects were enrolled. The prevalence of HBsAg and anti‐HCV (detected using a third‐generation, commercially available ELISA kit (Abbott Laboratories, Chicago, Illinois, USA)) as 13.7% and 6.3%, respectively, and 84 (0.7%) participants were positive for both HBsAg and anti‐HCV. In all, 642 anti‐HCV‐positive participants were tested for HCV RNA using a polymerase chain reaction assay (Cobas Amplicor Hepatitis C Virus Test, V.2.0; Roche Diagnostics, Branchburg, New Jersey, USA; detection limit: 50 IU/ml), and 478 (74.5%) of them were positive for HCV RNA. In addition to the manufacturer's instructions, which suggest rechecking for anti‐HCV if the data are <20% (0.8–0.99 signal to cut‐off (SCO)) of the cut‐off value (=1 SCO), in this study, the anti‐HCV tests were also rechecked if the data were 1–2 SCO. For avoiding false‐positive tests, anti‐HCV was also rechecked for the participants with positive anti‐HCV and negative HCV RNA. When comparing clinical factors between 642 anti‐HCV‐positive participants, with and without clearance of serum HCV RNA, we found that patients with positive HBsAg had a significantly higher proportion of HCV RNA clearance than those negative for HBsAg (p<0.001; table 11).). In a stepwise logistic regression analysis, positive HBsAg was the only independent factor significantly associated with negative HCV RNA in anti‐HCV participants (OR 0.348; 95% CI 0.211 to 0.574, p<0.001). HBV carriers were observed to have a significantly higher proportion of HCV RNA clearance than non‐carriers among men and women (fig 11).
Viral interferences and reciprocal viral interactions have been observed between HBV and HCV dual infection.7,8 Our previous study also showed that there might be a reciprocal viral interaction between HBV and HCV in patients with dual viral infection treated with interferon/ribavirin combination.9 Reports from Egypt and Japan2,3 were conducted in countries endemic for HCV where the prevalence of HBV carriers was <8% and they did not elucidate the influence the HBV infection. In our large‐scale community‐based study in an area endemic for HCV infection in a country hyperendemic for HBV, the important role of HBV carriers on HCV clearance was noteworthy and especially demonstrated. Besides, we did not find the effect of gender on the HCV clearance observed in previous studies.2,3 It seems necessary to conduct prospective, longitudinal studies in clarifying roles of gender or concurrent HBV infection on the HCV clearance rate in patients infected with HCV.
Competing interests: None.