Challenges for hepatitis B virus cure in resource-limited settings in sub-Saharan Africa

Navigating paediatric virology through the COVID‑19 era (Review)

The present review article presents the key messages of the 8th Workshop on Paediatric Virology organised virtually by the Institute of Paediatric Virology based on the island of Euboea in Greece. The major topics covered during the workshop were the following: i) New advances in antiviral agents and vaccines against cytomegalovirus; ii) hantavirus nephropathy in children; iii) human rhinovirus infections in children requiring paediatric intensive care; iv) complications and management of human adenovirus infections; v) challenges of post‑coronavirus disease 2019 (COVID‑19) syndrome in children and adolescents; and vi) foetal magnetic resonance imaging in viral infections involving the central nervous system. The COVID‑19 era requires a more intensive, strategic, global scientific effort in the clinic and in the laboratory, focusing on the diagnosis, management and prevention of viral infections in neonates and children.

Hepatitis B virus immunity prior to and after administration of a ‘booster’ dose of vaccine among health-care students at a South African university

Background

Health-care students (HCSs) are at risk of occupational exposure to hepatitis B virus (HBV) infection despite an effective hepatitis B vaccine (HepB) being available. The majority of current HCSs are born after HepB was introduced into the South African Expanded Programme on Immunisation in 1995. Thus, it is assumed that having received HepB in infancy, a single 'booster' dose would suffice. This study aimed to investigate HBV immunity prior to and after administration of a HepB 'booster' dose.

Methods

Hepatitis B surface antibody (anti-HBs) levels were determined in first year HCSs at the University of the Witwatersrand, before and after receiving the 'booster'. Participant demographics and HepB history were captured using a structured questionnaire.

Results

Before receiving the 'booster', 56% (101/180) had anti-HBs < 10 mIU/mL and were non-immune. A further 35% had anti-HBs levels of 10 - 99 mIU/mL, and 9% had ≥100 mIU/mL. <30% of HCSs self-reported completion of a three-dose primary series, which was significantly associated with higher baseline anti-HBs levels compared to those with a partial schedule (p = 0.045). Following vaccination, 39% (71/180) returned for follow-up with a significant median (IQR) increase of 476 (151 - 966) mIU/mL (p < 0.001). Of the 45 students who had non-immune baseline levels, 73% (33/45) responded with ≥100 mIU/mL, 16% (7/45) with 10 - 99 mIU/mL and 11% (5/45) remained non-immune. Levels of ≥100 mIU/mL were achieved by 100% of students with baseline levels ≥10 mIU/mL (n = 26).

Conclusion

More than half of the HCSs were not immune to HBV prior to receiving the recommended 'booster' vaccine. Following vaccination, 7% (5/71) remained unprotected. This study highlights that in the absence of vaccination records and without confirming the immune status of HCSs, it cannot be assumed that HCSs will be protected following a 'booster'. Policy reform and inclusion of serological tests for immunity prior to HCSs initiating clinical exposure are recommended.

Exploring the optimal vaccination strategy against hepatitis B virus in childhood (Review)

Vaccination against hepatitis B virus (HBV) remains the most effective strategy against HBV infection in humans. The present review summarized the optimal vaccination strategies against HBV in childhood. The following points are discussed: i) When and how the first HBV vaccines were developed; ii) the dosages, schedules and injection routes that are used for HBV vaccination; iii) the contraindications for HBV vaccination in the general paediatric population; iv) the challenges with the use of multivalent vaccines; v) the long-term immunogenicity and duration of protection against HBV; vi) the use of selective HBV vaccination and the hepatitis B immune globulin strategy in HBV-exposed infants; and vii) the effectiveness of the current HBV vaccination schemes. The present review is based on a Paediatric Virology Study Group (PVSG) webinar performed in the context of the 8th Workshop on Paediatric Virology.

Barriers that prevent adults living with HBV infection from participating in clinical research: experience from South Africa

High profile international goals have been set for the elimination of hepatitis B virus (HBV) infection as a public health threat by the year 2030. Developing and expanding equitable, accessible translational HBV research programmes that represent real-world populations are therefore an urgent priority for clinical and academic communities. We present experiences and insights by an expert interdisciplinary group focusing on barriers that impede adults living with HBV infection from participating in clinical studies. Our viewpoint describes barriers we have identified through working in a variety of settings across South Africa, including lack of education and awareness, experiences of stigma and discrimination, challenges for governance and data management, and a burden of complex morbidity. Through identifying these challenges, we propose solutions and interventions, highlight new approaches, and provide a framework for future research.

A roadmap for serum biomarkers for hepatitis B virus: current status and future outlook

Globally, 296 million people are infected with hepatitis B virus (HBV), and approximately one million people die annually from HBV-related causes, including liver cancer. Although there is a preventative vaccine and antiviral therapies suppressing HBV replication, there is no cure. Intensive efforts are under way to develop curative HBV therapies. Currently, only a few biomarkers are available for monitoring or predicting HBV disease progression and treatment response. As new therapies become available, new biomarkers to monitor viral and host responses are urgently needed. In October 2020, the International Coalition to Eliminate Hepatitis B Virus (ICE-HBV) held a virtual and interactive workshop on HBV biomarkers endorsed by the International HBV Meeting. Various stakeholders from academia, clinical practice and the pharmaceutical industry, with complementary expertise, presented and participated in panel discussions. The clinical utility of both classic and emerging viral and immunological serum biomarkers with respect to the course of infection, disease progression, and response to current and emerging treatments was appraised. The latest advances were discussed, and knowledge gaps in understanding and interpretation of HBV biomarkers were identified. This Roadmap summarizes the strengths, weaknesses, opportunities and challenges of HBV biomarkers.

Hepatitis B Virus Research in South Africa

Despite being vaccine-preventable, hepatitis B virus (HBV) infection remains the seventh leading cause of mortality in the world. In South Africa (SA), over 1.9 million people are chronically infected with HBV, and 70% of all Black chronic carriers are infected with HBV subgenotype A1. The virus remains a significant burden on public health in SA despite the introduction of an infant immunization program implemented in 1995 and the availability of effective treatment for chronic HBV infection. In addition, the high prevalence of HIV infection amplifies HBV replication, predisposes patients to chronicity, and complicates management of the infection. HBV research has made significant progress leading to better understanding of HBV epidemiology and management challenges in the SA context. This has led to recent revision of the national HBV infection management guidelines. Research on developing new vaccines and therapies is underway and progress has been made with designing potentially curative gene therapies against HBV. This review summarizes research carried out in SA on HBV molecular biology, epidemiology, treatment, and vaccination strategies.

Pimobendan Inhibits HBV Transcription and Replication by Suppressing HBV Promoters Activity

Current anti-HBV therapeutic strategy relies on interferon and nucleos(t)ide-type drugs with the limitation of functional cure, inducing hepatitis B surface antigen (HBsAg) loss in very few patients. Notably, the level of HBsAg has been established as an accurate indicator to evaluate the drug efficacy and predict the disease prognosis, thus exploring a novel drug targeting HBsAg will be of great significance. Herein, by screening 978 compounds from an FDA-approved drug library and determining the inhibitory function of each drug on HBsAg level in HepG2.2.15 cells supernatant, we identified that pimobendan (Pim) has a powerful antiviral activity with relatively low cytotoxicity. The inhibitory effect of Pim on HBsAg as well as other HBV markers was validated in HBV-infected cell models and HBV-transgenic mice. Mechanistically, real-time PCR and dual-luciferase reporter assay were applied to identify the partial correlation of transcription factor CAAT enhancer-binding protein α (C/EBPα) with the cccDNA transcription regulated by Pim. This indicates Pim is an inhibitor of HBV transcription through suppressing HBV promoters to reduce HBV RNAs levels and HBsAg production. In conclusion, Pim was identified to be a transcription inhibitor of cccDNA, thereby inhibiting HBsAg and other HBV replicative intermediates both in vitro and in vivo. This report may provide a promising lead for the development of new anti-HBV agent.

Tenofovir for prevention of mother to child transmission of hepatitis B in migrant women in a resource-limited setting on the Thailand-Myanmar border: a commentary on challenges of implementation

BACKGROUND

The aim of this manuscript is to highlight challenges in the implementation of maternal tenofovir disoproxil fumarate (tenofovir) for prevention of mother to child transmission (PMTCT) of hepatitis B virus (HBV) in resource limited setting. Current preventive strategies in resource-limited settings fail mainly due to prohibitive costs of hepatitis B immunoglobulin (HBIG) and a high proportion of homebirths, meaning both HBIG and hepatitis B birth dose vaccine are not given. A new strategy for PMTCT without the necessity of HBIG, could be daily tenofovir commenced early in gestation. Implementation challenges to early tenofovir for PMTCT can provide insight to elimination strategies of HBV as the burden of disease is high in resource-limited settings.

METHODS

Challenges encountered during implementation of a study of tenofovir for PMTCT before 20 weeks gestation in rural and resource-limited areas on the Thailand-Myanmar border were identified informally from trial study logbooks and formally from comments from patients and staff at monthly visits. ClinicalTrials.gov Identifier: NCT02995005.

MAIN BODY

During implementation 171 pregnant women were hepatitis B surface antigen (HBsAg) positive by point of-care test over 19 months (May-2018 until Dec-2019). In this resource-limited setting where historically no clinic has provided tenofovir for PMTCT of HBV, information provided by staff resulted in a high uptake of study screening (95.5% (84/88) when offered to pregnant women. False positive point-of-care rapid tests hinder a test and treat policy for HBV and development of improved rapid tests that include HBeAg and/or HBV DNA would increase efficiency. Integrated care of HBV to antenatal care, transport assistance and local agreements to facilitate access, could increase healthcare at this critical stage of the life course. As safe storage of medication in households in resource-limited setting may not be ideal, interactive counseling about this must be a routine part of care.

CONCLUSION

Despite challenges, results from the study to date suggest tenofovir can be offered to HBV-infected women in resource-limited settings before 20 weeks gestation with a high uptake of screening, high drug accountability and follow-up, with provision of transportation support. This commentary has highlighted practical implementation issues with suggestions for strategies that support the objective of PMTCT and the World Health Organization goal of HBV elimination by 2030.