Hepatitis B: changes in epidemiological features of Afro-descendant communities in Central Brazil

Abstract

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%) and low HBV vaccination like profile rates (2.0% and 21.0%) were observed. In 2015-2016, we reassessed HBV epidemiological and molecular features in these two communities to verify the impact of health actions adopted in the last years. 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 increased from 10.7% to 43.5% (2.0% to 45.9% in FD, 21.0% to 39.5% in SB) while susceptible subjects declined from 58.9% to 26.3% (55.3% to 18.8% in FD, 63.0% to 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. 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.

Figure 1

HBV serological profile among Afro-descendants according to age (years), Brazil Central, 2015–2016 (n = 331).

Figure 2

Comparison between HBV epidemiological features among Afro-descendants in the past (1999–2003) and present (2015–2016), Brazil Central.

Figure 3

Phylogenetic tree analysis of the pre-S/S/Pol region of HBV genome, containing 60 HBV/A1, 6 HBV/A2-quasiA3 isolates obtained from GenBank database in addition to consensus sequences from HBV genotypes B, C, D, E, F, G, H and I. FD isolates are shown in blue filled circles and SB isolates are shown in green filled circle. The phylogenetic tree was performed using the Maximum Likelihood method and bootstrap resampling test with 1,000 replicates.