Prevalence of hepatitis B and C viral markers among apparently healthy residents of the Socialist Republic of Vietnam (Southern Vietnam)

The aim of this study was to assess the prevalence of serological and molecular biological markers of viral hepatitis B and C among apparently healthy residents of the Southern Vietnam. The study material was represented by 397 blood serum samples collected from apparently healthy residents of the Southern Vietnam. The ELISA examination for presence of HBV and HCV markers involved HBsAg, anti-HBs IgG, anti-HBcore IgG, and anti-HCV qualitative determination. For HBV DNA and HCV RNA detection, nucleic acids were extracted from serum blood, and a test for virus detection was carried out by real-time PCR with hybridization fluorescence detection. Amplification and subsequent sequencing of HBV and HCV were performed using nested PCR with paired overlapping primers jointly flanking the target regions. Analysis of the overall prevalence of serological markers showed that among the apparently healthy individuals anti-HBsAg and anti-HCV antibodies were detected in 12.3% (95% CI: 9.27–15.99%) and 3.27% (95% CI: 1.76–5.53%) of individuals, respectively. The prevalence of HBsAg in men (19.1%) significantly exceeded that of found in women (5.9%), χ2 = 14.688 with p = 0.0001, df = 1, calculated odds ratio OR = 3.751 (95% CI: 1.892–7.439). Among apparently healthy patients, taking into account HBsAg-positive and negative samples, HBV DNA was detected in 26.95% (95% CI: 22.65–31.6%). HBV phylogenetic analysis showed that subtype B4 prevalence comprised 64.49%. Subtypes C1 (14.95%), B2 (9.35%), C2 (6.54%), C3 (0.93%), and C5 (3.74%) were also identified. HCV RNA was detected in 7 samples, which accounted for 1.76% (95% CI: 0.71–3.6%). Phylogenetic analysis showed that all HCV isolates belong to genotype 6, subtype 6a (100%).