Hepatitis B virus (HBV) subgenotypes may be related to clinical outcomes and response to antiviral therapy. Most Brazilian studies on HBV subgenotypes are restricted to some regions and to specific population groups. Here, we provide an insight about genetic diversity of HBV subgenotypes in 321 serum samples from all five geographical regions, providing a representative overview of their circulation among chronic carriers. Overall, HBV/A1 was the most prevalent subgenotype, being found as the major one in all regions except in South Brazil. Among HBV/D samples, subgenotype D3 was the most prevalent, found in 51.5%, followed by D2 (27.3%) and D4 (21.2%). D2 and D3 were the most prevalent subgenotypes in South region, with high similarity with European strains. D4 was found in North and Northeast region and clustered with strains from Cape Verde and India. For HBV/F, the most frequent subgenotype was F2 (84.1%), followed by F4 (10.1%) and F1 (5.8%), closely related with strains from Venezuela, Argentina and Chile, respectively. Phylogeographic analyses were performed using an HBV full-length genome obtained from samples infected with genotypes rarely found in Brazil (B, C, and E). According to Bayesian inference, HBV/B2 and HBV/C2 were probably introduced in Brazil through China, and HBV/E from Guinea, all of them mostly linked to recent events of human migration. In conclusion, this study provided a comprehensive overview of the current circulation of HBV subgenotypes in Brazil. Our findings might contribute to a better understand of the dynamics of viral variants, to establish a permanent molecular surveillance on the introduction and dispersion patterns of new strains and, thus, to support public policies to control HBV dissemination in Brazil.

Hepatitis A virus (HAV) outbreaks among men who have sex with men (MSM) have been reported worldwide and associated primarily with sexual transmission through oral-anal sex. Here, we provide the molecular and evolutionary description of a European strain, linked to HAV outbreaks among MSM, detected in a Brazilian homosexual couple. Bayesian analysis provided evidence that the viral isolates were introduced in Brazil from Spain between the end of 2016 and the beginning of 2017.

Hepatitis B virus (HBV) is an enveloped virus that induces chronic liver disease. HBV has been classified into eight genotypes (A–H) according to its genome sequence by using Sanger sequencing or reverse hybridization. Sanger sequencing is often restricted to analyzing the S gene and is inaccurate for detecting minority genetic variants, whereas reverse hybridization detects only known mutations. Next-generation sequencing (NGS) is a robust tool for clinical virology with different protocols available. The objective of this study was to develop a new method for the study of viral genetic polymorphisms or more accurate genotyping using genome amplification followed by NGS. Plasma obtained from five chronically infected HBV individuals was used for viral DNA isolation. HBV full-genome PCR amplification was the enrichment method for NGS. Primers were used to amplify all HBV genotypes in three overlapping amplicons, following a tagmentation step and Illumina NGS. For phylogenetic analysis, sequences were extracted from the HBVdb database. We were able to amplify a full HBV genome; further, NGS was shown to be a robust method and allowed better genotyping, mainly in patients carrying mixed genotypes, classified according to other techniques. This new method may be significant for whole genome analyses, including other viruses.

Background: Despite an existing safe and effective vaccine for hepatitis B virus (HBV), it is still a major public health concern. Nowadays, several drugs are used to treat chronic hepatitis B; however, full healing remains controversial. The viral covalently closed circular DNA (cccDNA) formed by HBV forms a major challenge in its treatment, as does the ability of HBV to integrate itself into the host genome, which enables infection reactivation. Interfering RNA (RNAi) is a gene-silencing post-transcriptional mechanism which forms as a promising alternative to treat chronic hepatitis B. The aim of the present review is to assess the evolution of hepatitis B treatment approaches based on using RNA interference. Methods: Data published between 2016 and 2023 in scientific databases (PubMed, PMC, LILACS, and Bireme) were assessed. Results: In total, 76,949 articles were initially identified and quality-checked, and 226 eligible reports were analyzed in depth. The main genomic targets, delivery systems, and major HBV therapy innovations are discussed in this review. This review reinforces the therapeutic potential of RNAi and identifies the need for conducting further studies to fill the remaining gaps between bench and clinical practice.

This study aims to evaluate the epidemiological and molecular features associated with HAV transmission in adults in Rio de Janeiro during a period of increased registered cases of HAV (2017–2018). Socio-epidemiological data and serum samples from anti-HAV IgM+ individuals were obtained. HAV RNA was RT-PCR amplified and sequenced for further phylogenetic and phylogeographic analyses. From fifty-two HAV IgM+ individuals, most were men (78.85%; p = 0.024), aged 20–30 years old (84.61%; p < 0.001), resided in the Rio de Janeiro north zone (31/52; 59.62%; p = 0.001), and are men who have sex with men (MSM) (57.69%; p = 0.002). Sexual practices were more frequent (96%) than others risk factors (food-borne (44%), water-borne (42.31%), and parenteral (34.62%)). Individuals who traveled to endemic regions had a 7.19-fold (1.93–36.04; p < 0.01) increased risk of HAV. Phylogenetic analysis revealed four distinct clades of subgenotype IA, three of them comprised sequences from European/Asian MSM outbreaks and one from Brazilian endemic strains. Bayesian Inference showed that the imported strains were introduced to Brazil during large mass sportive events. Sexual orientation and sexual practices may play a role in acquiring HAV infection. Public policies targeting key populations must be implemented to prevent further dissemination of HAV and other STIs.

In Brazil, hepatitis C treatment has been evolving significantly with the licensing of direct-acting antivirals (DAAs). However, viral determinants (amino acid substitutions in hepatitis C virus (HCV) genome and infective genotype) associated with host factors (hepatic condition and prior HCV therapy) might limit the achievement of sustained virologic response (SVR). Here, we described two case reports in which the occurrence of HCV NS5A mutations A30K (subtype 3a) and Y93N (subtype 1a) might have influenced daclatasvir (DCV)/sofosbuvir (SOF) combined therapy non-response. Despite high response rates for DAA combined therapies in Brazil, these case reports stated the importance of an investigation about how to manage a DAA treatment failure since a combination of factors, especially the occurrence of resistance substitutions, could impact a rescue therapy with new available antivirals in clinical routine.