Hepatitis B: changes in epidemiological features of Afrodescendant communities in Central Brazil

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Introduction: Hepatitis B virus (HBV) infection is still a concern in vulnerable populations. In a study performed by our team in 1999–2003 in two Afro-Brazilian communities, Furnas dos Dionísios (FD) and São Benedito (SB), high prevalence rates of HBV exposure (42.7% and 16.0%, respectively), high susceptibility to HBV (55.3% and 63.0%, respectively) and low HBV vaccination like profile rates (2.0% and 21.0%, respectively) were observed. Objective: In 2015–2016, we reassessed epidemiological and molecular features of HBV in these two communities to verify the impact of health actions adopted in the past years. Methods: Serum samples were screened by enzyme-linked immunosorbent assay (ELISA) for the presence of HBsAg, hepatitis B core antibody (total anti-HBc), and hepatitis B surface antibody (anti-HBs) (Biokit S.A., Barcelona, Spain). Cobas® e601 analyzer (Roche Diagnostics, Mannheim, Germany) was used to test the presence of HBeAg, anti- -HBe, and anti-HBc IgM in HBsAg-positive samples. The complete pre-S/S HBV region (nt 2826–nt 841) was amplified by semi-nested polymerase chain reaction (PCR). Results: The prevalence rate of HBV exposure among the enrolled 331 subjects was 35.3% in FD and 21.8% in SB. HBV chronic infection (5.8% in FD, 4.9% in SB) remained high. The rate of HBV vaccination like profile rate increased from 10.7% to 43.5% (2.0%–45.9% in FD, 21.0%–39.5% in SB), while susceptible subjects declined from 58.9% to 26.3% (55.3%– 18.8% in FD, 63.0%–38.7% in SB). Among 18 HBsAg-positive samples, 13 were successfully sequenced (pre-S/S region). Phylogenetic analyses showed that all isolates belong to HBV subgenotype A1, clustering within the Asian-American clade. Conclusion: Despite the maintenance of high prevalence rate of HBV exposure over these 13 years of surveillance, significant improvements were observed, reinforcing the importance of facilitated HBV vaccination to difficult-to-access population to close gaps in prevention.

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