Development and evaluation of a simple treatment eligibility score (HEPSANET) to decentralise hepatitis B care in Africa: a cross-sectional study

BACKGROUND

Hepatitis B virus (HBV) elimination requires expanding and decentralising HBV care services. However, peripheral health facilities lack access to diagnostic tools to assess eligibility for antiviral therapy. Through the Hepatitis B in Africa Collaborative Network (HEPSANET), we aimed to develop and evaluate a score using tests generally available at lower-level facilities, to simplify the evaluation of antiviral therapy eligibility in people living with HBV.

METHODS

We surveyed the availability of clinical and laboratory parameters across different health-care levels in sub-Saharan Africa. We used data from the HEPSANET dataset, the largest cross-sectional dataset of treatment-naive people living with HBV in sub-Saharan Africa, to derive and validate the score. Participants from this dataset were included in the analysis if they were aged 18 years or older and had liver fibrosis stages determined by a liver stiffness measurement or liver histopathology. Participants with co-infections or metabolic disorders were excluded. We allocated participants to the derivation and validation sets by geographical site. In the derivation set, we used stepwise logistic regression to identify the best performing parameters for identifying participants that met the 2017 European Association for the Study of the Liver (EASL) criteria. Regression coefficients were converted into integer points to construct simplified algorithms for different health-care levels. In the validation set, we estimated the area under the receiver operating characteristic, sensitivity, and specificity of the simplified algorithm for identifying antiviral therapy eligibility defined by the 2017 EASL criteria.

FINDINGS

At 11 sites from eight countries that returned surveys, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelet count were generally available at district hospital levels, and hepatitis B e antigen and point-of-care HBV DNA tests were available only at regional and provincial hospital levels or above. Among 2895 participants included from the HEPSANET database (1740 [60·1%] male, 1155 [39·9%] female), 409 (14·1%) met EASL antiviral therapy eligibility criteria. In the derivation set, the optimal district-level hospital score was: ALT (IU/L), less than 40 (0 points), 40-79 (+1), 80 or greater (+2); AST (IU/L), less than 40 (0), 40-79 (+1), 80 or greater (+2); and platelet counts (109/L), less than 100 (+2), 100-149 (+1), 150 or greater (0). When combined with family history and clinical data for decompensated cirrhosis that do not require any biological tests, a cut-off of 2 points or more had a sensitivity and specificity of 82% (95% CI 76-86) and 95% (93-96) to identify treatment-eligible individuals in the derivation set, and 78% (71-85) and 87% (86-89) in the validation set, respectively.

INTERPRETATION

Using a score incorporating platelet counts, AST, and ALT, the majority of people living with HBV requiring antiviral therapy can be identified. Our findings suggest that clinical staging can be decentralised down to district hospital level in sub-Saharan Africa.

FUNDING

European Association for the Study of the Liver Foundation, John C Martin Foundation.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Treat All versus targeted strategies to select HBV-infected people for antiviral therapy in The Gambia, west Africa: a cost-effectiveness analysis

BACKGROUND

Global elimination of hepatitis B virus (HBV) requires expanded uptake of antiviral therapy, potentially by simplifying testing algorithms, especially in resource-limited countries. We evaluated the effectiveness, cost-effectiveness, and budget impact of three strategies that determine eligibility for anti-HBV treatment, as compared with the WHO 2015 treatment eligibility criteria, in The Gambia.

METHODS

We developed a microsimulation model of natural history using data from the Prevention of Liver Fibrosis and Cancer in Africa programme (known as PROLIFICA) in The Gambia, for an HBV-infected cohort of individuals aged 20 years. The algorithms included in the model were a conventional strategy using the European Association for the Study of the Liver (EASL) 2017 criteria, a simplified algorithm using hepatitis B e antigen and alanine aminotransferase (the Treatment Eligibility in Africa for the Hepatitis B Virus [TREAT-B] score), a Treat All approach for all HBV-infected individuals, and the WHO 2015 criteria. Outcomes to measure effectiveness were disability-adjusted life years (DALYs) and years of life saved (YLS), which were used to calculate incremental cost-effectiveness ratios (ICERs) with the WHO 2015 criteria as the base-case scenario. Costs were assessed from a modified social perspective. A budget impact analysis was also done. We tested the robustness of results with a range of sensitiviy analyses including probabilistic sensitivity analysis.

FINDINGS

Compared with the WHO criteria, TREAT-B resulted in 4877 DALYs averted and Treat All resulted in 9352 DALYs averted, whereas the EASL criteria led to an excess of 795 DALYs. TREAT-B was cost-saving, whereas the ICER for Treat All (US$2149 per DALY averted) was higher than the cost-effectiveness threshold for The Gambia (0·5 times the country's gross domestic product per capita: $352). These patterns did not change when YLS was the outcome. In a modelled cohort of 5000 adults (aged 20 years) with chronic HBV infection from The Gambia, the 5-year budget impact was $1·14 million for Treat All, $0·66 million for TREAT-B, $1·03 million for the WHO criteria, and $1·16 million for the EASL criteria. Probabilistic sensitivity analysis indicated that among the Treat All, EASL, and TREAT-B algorithms, Treat All would become the most preferred strategy only with a willingness-to-pay threshold exceeding approximately $72 000 per DALY averted or $110 000 per YLS.

INTERPRETATION

Although the Treat All strategy might be the most effective, it is unlikely to be cost-effective in The Gambia. A simplified strategy such as TREAT-B might be a cost-saving alternative.

FUNDING

UK Research and Innovation (Medical Research Council).

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Clinical characteristics and outcomes of patients with cirrhosis and hepatocellular carcinoma in The Gambia, west Africa: a prospective cohort study

BACKGROUND

Chronic liver disease is a major cause of premature death in sub-Saharan Africa. Efficacy of antiviral therapy among patients with hepatitis B virus (HBV)-related cirrhosis is not well established in Africa. We described the clinical characteristics and outcomes of patients with cirrhosis and hepatocellular carcinoma in The Gambia and assessed the impact of tenofovir disoproxil fumarate (TDF) on survival of HBV-infected patients with cirrhosis.

METHODS

In this prospective cohort study, we followed up adults who were consecutively diagnosed with cirrhosis or hepatocellular carcinoma between 2012 and 2015 in The Gambia, west Africa. Patients with chronic HBV infection and cirrhosis, without hepatocellular carcinoma, were offered TDF. Primary outcome was overall survival. To determine the effect of TDF on survival, we performed a Cox proportional hazard regression model with inverse probability of treatment weighting (IPTW) based on propensity score.

FINDINGS

Of 529 patients enrolled in this study, 336 patients (252 with hepatocellular carcinoma and 84 with cirrhosis) were analysed. Patients were predominantly male (253 [75%] men and 83 [25%] women), with a median age of 42 years (IQR 33-55). 276 (84%) of 327 of patients with data were positive for HBV biomarkers, 31 (10%) of 311 were positive for hepatitis C virus antibodies, and 22 (10%) of 223 were positive for hepatitis D virus antibodies. 64% of patients with hepatocellular carcinoma had multifocal tumour, with a median size of 7·5 cm (IQR 5·4-10·8). 173 patients with hepatocellular carcinoma and 70 patients with cirrhosis were included in the survival analysis. Median survival was 1·5 months (95% CI 1·1-2·0) in patients with hepatocellular carcinoma and 17·1 months (11·2-24·0) in patients with cirrhosis (log-rank p<0·0001). In patients with hepatocellular carcinoma, ascites (hazard ratio [HR] 1·78, 95% CI 1·21-2·60), partial or complete portal thrombosis (HR 2·61, 1·58-4·30), and platelet count (HR 1·80, 1·19-2·70) were independent predictive factors of mortality at baseline. In HBV-infected patients with cirrhosis, median turnaround time between cirrhosis diagnosis and TDF initiation was 4·9 months (IQR 3·2-7·3). In IPTW analysis, TDF treatment was associated with improved survival in patients with HBV-related cirrhosis (adjusted HR 0·14, 0·06-0·34; p<0·0001).

INTERPRETATION

These results highlight poor survival of patients with cirrhosis or hepatocellular carcinoma as well as the effectiveness of TDF in reducing the premature mortality of patients with cirrhosis and HBV infection. Interventions for early diagnosis and treatment of cirrhosis as well as screening programmes for hepatocellular carcinoma are urgently required in Africa.

FUNDING

European Commission and Medical Research Council UK.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Informing a target product profile for rapid tests to identify HBV-infected pregnant women with high viral loads: a discrete choice experiment with African healthcare workers

BACKGROUND

Elimination of mother-to-child transmission of hepatitis B virus (HBV) requires infant immunoprophylaxis and antiviral prophylaxis for pregnant women with high viral loads. Since real-time polymerase chain reaction (RT-PCR), a gold standard for assessing antiviral eligibility, is neither accessible nor affordable for women living in low-income and middle-income countries (LMICs), rapid diagnostic tests (RDTs) detecting alternative HBV markers may be needed. To inform future development of the target product profile (TPP) for RDTs to identify highly viremic women, we used a discrete choice experiment (DCE) and elicited preference and trade-off of healthcare workers (HCW) in Africa between the following four attributes of fictional RDTs: price, time-to-result, diagnostic sensitivity, and specificity.

METHODS

Through an online questionnaire survey, we asked participants to indicate their preferred test from a set of two RDTs in seven choice tasks with varying levels of the four attributes. We used mixed multinomial logit models to quantify the utility gain or loss generated by each attribute. We attempted to define minimal and optimal criteria for test attributes that can satisfy ≥ 70% and ≥ 90% of HCWs, respectively, as an alternative to RT-PCR.

RESULTS

A total of 555 HCWs from 41 African countries participated. Increases in sensitivity and specificity generated significant utility and increases in cost and time-to-result generated significant disutility. The size of the coefficients for the highest attribute levels relative to the reference levels were in the following order: sensitivity (β = 3.749), cost (β = -2.550), specificity (β = 1.134), and time-to-result (β = -0.284). Doctors cared most about test sensitivity, while public health practitioners cared about cost and midwives about time-to-result. For an RDT with 95% specificity, costing 1 US$, and yielding results in 20 min, the minimally acceptable test sensitivity would be 82.5% and the optimally acceptable sensitivity would be 87.5%.

CONCLUSIONS

African HCWs would prefer an RDT with the following order of priority: higher sensitivity, lower cost, higher specificity, and shorter time-to-result. The development and optimization of RDTs that can meet the criteria are urgently needed to scale up the prevention of HBV mother-to-child transmission in LMICs.

Cost-effectiveness of different monitoring strategies in a screening and treatment programme for hepatitis B in The Gambia

Background

Clinical management of chronic hepatitis B virus (HBV) infection is complex and access to antiviral treatment remains limited in sub-Saharan Africa. International guidelines recommend monitoring at least annually for disease progression among HBV-infected people not meeting treatment criteria at initial diagnosis. This study aimed to assess the impact and cost-effectiveness of alternative strategies for monitoring.

Methods

We used a mathematical model of HBV transmission and natural history, calibrated to all available West African data, to project the population-level health impact, costs and cost-effectiveness of different monitoring strategies for HBV-infected individuals not initially eligible for antiviral treatment. We assumed that these patients were found in the year 2020 in a hypothetical community-based screening programme in The Gambia. Monitoring frequencies were varied between every 5 and every 1 year and targeted different age groups.

Results

The currently recommended annual monitoring frequency was likely to be not cost-effective in comparison with other strategies in this setting. 5-yearly monitoring in 15-45-year olds, at US$338 per disability-adjusted life year averted, had the highest probability of being the most effective cost-effective monitoring strategy.

Conclusions

Monitoring less frequently than once a year is a cost-effective strategy in a community-based HBV screening and treatment programme in The Gambia, with the optimal strategy depending on the cost-effectiveness threshold. Efficiencies may be gained by prioritising the 15-45-year age group for more intensive monitoring.

Mac-2 binding protein glycosylation isomer (M2BPGi) to evaluate liver fibrosis and cancer in HBV-infected patients in West Africa

Background

To reduce mortality associated with hepatitis B virus (HBV) infection, timely detection of cirrhosis and early-stage hepatocellular carcinoma (HCC) is essential. In low-income countries, however, HBV-infected people have limited access to liver histopathology, a reference test. Recently, Asian studies have suggested the usefulness of an inexpensive serum biomarker called Mac-2 binding protein glycosylation isomer (M2BPGi) in staging liver fibrosis and predicting HCC in HBV-infected patients.

Methods

We systematically searched PubMed for studies examining the performance of M2BPGi in staging liver fibrosis in HBV-infected people, published up to September 21, 2021, to elucidate the knowledge gap. We then conducted a cross-sectional study of 339 HBV-infected patients in The Gambia (cirrhosis  = 65, HCC = 73, non-cirrhosis non-HCC = 201). We evaluated the association of M2BPGi with cirrhosis and HCC by computing odds ratios (ORs) derived from logistic regression. We also assessed the performance of M2BPGi to stage liver fibrosis in 49 patients who underwent liver biopsy (derivation set) and 217 patients with transient elastography (validation set). Using the derivation set we drew the receiver operating characteristics (ROC) curves to identify optimal M2BPGi thresholds to indicate significant fibrosis and cirrhosis using biopsy as a reference. We then applied these cut-offs to the validation set to obtain its sensitivity and specificity for indicating significant fibrosis and cirrhosis using transient elastography as a reference.

Results

The systematic review identified 13 studies, all of which were conducted in East Asia and none in Africa. In The Gambia, positive M2BPGi was significantly associated with both cirrhosis (adjusted OR = 7.8, 95% CI = 3.1-19.7) and HCC (adjusted OR = 10.1, 2.6-40.2). The areas under the ROC curve (AUROC) in the derivation and validation set were 0.62 and 0.78, respectively, to diagnose significant fibrosis, and 0.80 and 0.89, respectively, to diagnose cirrhosis. By applying the optimal cut-offs, the sensitivity and specificity in the validation set were 61.5% and 93.4%, respectively, to diagnose significant fibrosis, and 72.5% and 92.2%, respectively, for cirrhosis.

Conclusions

To the best of our knowledge, this is the first evaluation of M2BPGi in HBV-infected African population. The findings supported its accuracy in the diagnosis of cirrhosis in HBV-infected patients in West Africa.

Hepatocellular carcinoma: measures to improve the outlook in sub-Saharan Africa

Hepatocellular carcinoma is a leading public health concern in sub-Saharan Africa, and it is most prevalent in young adults (median 45 years [IQR 35-57]). Overall, outcomes are poor, with a median survival of 2·5 months after presentation. Major risk factors for hepatocellular carcinoma are hepatitis B virus (HBV), hepatitis C virus, aflatoxin B1 exposure, and alcohol consumption, with metabolic dysfunction-associated fatty liver disease slowly emerging as a risk factor over the past few years. Crucially, these risk factors are preventable and manageable with effective implementation of the HBV birth-dose vaccination, treatment of chronic viral hepatitis, provision of harm reduction services, and by decreasing aflatoxin B1 exposure and harmful alcohol consumption. Primary prevention is central to the management of hepatocellular carcinoma, especially in poorly resourced environments. Effective screening and surveillance programmes with recall policies need to be implemented, because detection and curative management of hepatocellular carcinoma is possible if it is detected at an early stage, even in countries with minimal resources, with appropriate upskilling of medical personnel. The establishment of centres of excellence with advanced diagnostic and therapeutic capabilities within countries should improve hepatocellular carcinoma outcomes and assist in driving the implementation of much needed systematic data systems focused on hepatocellular carcinoma to establish the accurate burden in sub-Saharan Africa. Such data would support the public health importance of hepatocellular carcinoma and provide a strong basis for advocacy, programme development, resource allocation, and monitoring of progress in reducing mortality.

HBV continuum of care using community- and hospital-based screening interventions in Senegal: Results from the PROLIFICA programme

Background & Aims

Strategies to implement HBV screening and treatment are critical to achieve HBV elimination but have been inadequately evaluated in sub-Saharan Africa (sSA).

Methods

We assessed the feasibility of screen-and-treat interventions in 3 real-world settings (community, workplace, and hospital) in Senegal. Adult participants were screened using a rapid HBsAg point-of-care test. The proportion linked to care, the proportion who had complete clinical staging (alanine transaminase [ALT], viral load, and FibroScan®), and the proportion eligible for treatment were compared among the 3 intervention groups.

Results

In 2013-2016, a total of 3,665 individuals were screened for HBsAg in the community (n = 2,153) and in workplaces (n = 1,512); 199/2,153 (9.2%) and 167/1,512 (11%) were HBsAg-positive in the community and workplaces, respectively. In the hospital setting (outpatient clinics), 638 HBsAg-positive participants were enrolled in the study. All infected participants were treatment naïve. Linkage to care was similar among community-based (69.9%), workplace-based (69.5%), and hospital-based interventions (72.6%, p = 0.617). Of HBV-infected participants successfully linked to care, full clinical staging was obtained in 47.5% (66/139), 59.5% (69/116), and 71.1% (329/463) from the community, workplaces, and hospitals, respectively (p <0.001). The proportion eligible for treatment (EASL criteria) differed among community- (9.1%), workplace- (30.4%), and hospital-based settings (17.6%, p = 0.007). Acceptability of antiviral therapy, adherence, and safety at 1 year were very good.

Conclusions

HBV screen-and-treat interventions are feasible in non-hospital and hospital settings in Senegal. However, the continuum of care is suboptimal owing to limited access to full clinical staging. Improvement in access to diagnostic services is urgently needed in sSA.

Lay summary

Hepatitis B infection is highly endemic in Senegal. Screening for infection can be done outside hospitals, in communities or workplaces. However, the hepatitis B continuum of care is suboptimal in Senegal and needs to be simplified to scale-up diagnosis and treatment coverage.

Prevalence and Clinical Significance of Occult Hepatitis B Infection in The Gambia, West Africa

BACKGROUND

Prevalence and clinical outcomes of occult hepatitis B infection (OBI) have been poorly studied in Africa.

METHODS

Using the PROLIFICA cohort, we compared the prevalence of OBI between hepatitis B surface antigen (HBsAg)-negative healthy adults screened from the general population (controls) and HBsAg-negative patients with advanced liver disease (cases), and estimated the population attributable fraction for the effect of OBI on advanced liver disease.

RESULTS

OBI prevalence was significantly higher among cases (15/82, 18.3%) than controls (31/330, 9.4%, P = .03). After adjusting for age, sex, and anti-hepatitis C virus (HCV) serology, OBI was significantly associated with advanced liver disease (odds ratio, 2.8; 95% confidence interval [CI], 1.3-6.0; P = .006). In HBsAg-negative people, the proportions of advanced liver disease cases attributable to OBI and HCV were estimated at 12.9% (95% CI, 7.5%-18.1%) and 16.9% (95% CI, 15.2%-18.6%), respectively.

CONCLUSIONS

OBI is endemic and an independent risk factor for advanced liver disease in The Gambia, West Africa. This implies that HBsAg-negative people with liver disease should be systematically screened for OBI. Moreover, the impact of infant hepatitis B immunization to prevent end-stage liver disease might be higher than previous estimates based solely on HBsAg positivity.

Prevalence of occult hepatitis B virus infection in adults: a systematic review and meta-analysis

Background

Despite growing concerns about transmissibility and clinical impact, occult hepatitis B virus (HBV) infection has received little attention in the hepatitis elimination agenda. We aimed to estimate the prevalence of occult HBV infection at a global and regional scale and in specific populations.

Methods

For this systematic review and meta-analysis, we searched the MEDLINE, Embase, Global Health, and Web of Science databases for articles published in any language between Jan 1, 2010, and Aug 14, 2019. We included original articles and conference abstracts of any study design that reported the proportion of HBsAg-negative adults (aged ≥18 years) who are positive for HBV DNA (ie, people with occult HBV infection). The prevalence of occult HBV infection was pooled, using the DerSimonian-Laird random-effects model, in the general population and specific groups defined by the type of study participants (blood donors; other low-risk populations; high-risk populations; and people with advanced chronic liver disease), and stratified by HBV endemicity in each country. We also assessed the performance of anti-HBc as an alternative biomarker to detect occult HBV infection. The study was registered with PROSPERO, CRD42019115490.

Findings

305 of 3962 articles were eligible, allowing a meta-analysis of 140 521 993 individuals tested for HBV DNA. Overall, only two studies evaluated occult HBV infection in the general population, precluding unbiased global and regional estimates of occult HBV infection prevalence. In blood donors, occult HBV infection prevalence mirrored HBV endemicity: 0·06% (95% CI 0·00–0·26) in low-endemicity countries, 0·12% (0·04–0·23) in intermediate-endemicity countries, and 0·98% (0·44–1·72), in high-endemicity countries (p=0·0012). In high-risk groups, occult HBV infection prevalence was substantial, irrespective of endemicity: 5·5% (95% CI 2·9–8·7) in low-endemicity countries, 5·2% (2·5–8·6) in intermediate-endemicity countries, and 12·0% (3·4–24·7) in high-endemicity countries. The pooled sensitivity of anti-HBc to identify occult HBV infection was 77% (95% CI 62–88) and its specificity was 76% (68–83).

Interpretation

A substantial proportion of people carry occult HBV infection, especially among high-risk groups across the globe and people living in highly endemic countries. Occult HBV infection should be part of the global viral hepatitis elimination strategy.

Funding

None.

Clinical utility of the 'Determine HBsAg' Point-of-Care Test for Diagnosis of Hepatitis B Surface Antigen in Africa

INTRODUCTION

Chronic infection with hepatitis B virus (HBV) is a leading cause of morbidity and death, especially in sub-Saharan Africa (sSSA), where approximately 60 million adults are infected. More than 90% of these patients are unaware of their HBV status.

AREAS COVERED

Scaling-up of HBV screening programs in SSA are essential to increase diagnosis, linkage to care and access to treatment, and will ultimately reduce HBV disease burden to achieve WHO hepatitis elimination targets. Such scale up will rely on inexpensive rapid point-of-care (POC) tests, especially in remote areas where gold standard serological assays are not routinely available. This review discusses the diagnostic performance and clinical utility of the Determine™ (Abbott, USA) hepatitis B surface Antigen (HBsAg) POC test for improving HBV screening in SSA, in light with others available HBsAg rapid tests.

EXPERT OPINION

The Determine™ HBsAg POC test has demonstrated relatively good diagnostic accuracy at the low cost, in the African field and laboratory and should be used for large scale mass screening of HBV infection in Africa.

Clinical utility of quantifying hepatitis B surface antigen in African patients with chronic hepatitis B

The clinical utility of quantifying hepatitis B surface antigen (qHBsAg) levels in African subjects with chronic hepatitis B virus (HBV) infection has been poorly documented. From a multicentre cohort of 944 HBV-infected African patients, we aimed to assess whether qHBsAg alone can accurately identify i) those in a HBeAg-negative chronic HBV infection phase at low risk of liver disease progression and ii) those in need of antiviral therapy according to the 2017 EASL guidelines. We analysed 770 HBV mono-infected treatment-naïve patients, mainly males (61%) from West Africa (92%), median age 35 years (IQR: 30-44), median HBV DNA: 95.6 IU/ml (10.0-1,300.0), median qHBsAg 5,498 IU/ml (1,171-13,000) and HBeAg-pos 38 (5%). A total of 464/770 (60.2%) patients were classified as HBeAg-negative chronic infection (median age 36 years (31-46), median ALT 23 IU/l (18-28), median HBV-DNA 33.5 IU/ml (3.8-154.1), median LSM 4.8 kPa (4.1-5.8)) and qHBsAg levels had poor accuracy to identify these subjects with an AUROC at 0.58 (95%CI: 0.54-0.62), sensitivity 55.0% and specificity 55.6%; 118/770 (15.3%) patients were eligible for treatment according to the 2017 EASL criteria. qHBsAg correlated poorly with HBV DNA and had poor accuracy to select patients for antiviral therapy with an AUROC at 0.54 (0.49-0.60), sensitivity 46.6% and specificity 46.9%. In African treatment-naïve HBV-infected subjects, the clinical utility of qHBsAg to identify subjects in HBeAg-negative infection phase or subjects eligible for antiviral therapy seems futile. Whether qHBsAg levels can be used as a predictor of long-term liver complications in Africa needs to be further investigated.

Hepatitis B virus preS2Δ38-55 variants: A newly identified risk factor for hepatocellular carcinoma

BACKGROUND & AIMS

Although HBV is a major cause of death in Africa, its genetic variability has been poorly documented. This study aimed to address whether HBV genotype and surface gene variants are associated with HBV-related liver disease in The Gambia.

METHODS

We conducted a case-control study nested in the Prevention of Liver Fibrosis and Cancer in Africa programme. Consecutive treatment-naive patients with chronic HBV infection and detectable viral load were recruited: 211 controls with no significant liver disease and 91 cases (56 cirrhosis and 35 HCC cases). HBV genotypes and surface gene variants were determined by Sanger sequencing or next-generation sequencing (NGS) in serum DNA. Aflatoxin B1 (AFB1)-specific codon 249 TP53 mutation was determined by NGS in circulating cell-free plasma DNA.

RESULTS

In phylogenetic analysis, 85% of individuals carried HBV genotype E, 14% genotype A, and 1% A/E recombinant viruses. Surface gene variants were more frequently observed in cases (43% and 57% in cirrhosis and HCC cases, respectively) than controls (25%; p <0.001), with preS2 deletions between nucleotides 38-55 (preS2Δ38-55) being the main genetic variant detected. In multivariable analysis, HBeAg seropositivity, low HBsAg levels, and HDV seropositivity were significantly associated with cirrhosis and HCC, whilst older age, higher viral load, genotype A, preS2Δ38-55, and AFB1 exposure were only associated with HCC. There was a multiplicative joint effect of preS2Δ38-55 variants with HBeAg seropositivity (odds ratio [OR] 43.1 [10.4-177.7]), high viral load >2,000 IU/ml (OR 22.7 [8.0-64.9]), HBsAg levels <10,000 IU/ml (OR 19.0 [5.5-65.3]), and AFB1 exposure (OR 29.3 [3.7-230.4]) on HCC risk.

CONCLUSIONS

This study identified a hotspot for HBV preS2 deletions as a strong independent factor for HCC in The Gambia, with HBV genotypes and AFB1 exposure contributing to the high liver cancer risk.

LAY SUMMARY

Although HBV-related liver disease is highly prevalent in sub-Saharan Africa, the associated virological characteristics are poorly studied. Using clinical data from African patients chronically infected with HBV, an assessment of the virological variability (genotypes and mutations) and exposure to AFB1, a toxin often contaminating food, was carried out. Our results show that HBV genotypes, the presence of a highly prevalent mutant form of HBV, and AFB1 exposure contribute to the high liver cancer risk in this population.

Lessons from the Ebola epidemics and their applications for COVID-19 pandemic response in sub-Saharan Africa

COVID-19, caused by a novel coronavirus named SARS-CoV-2, was identified in December 2019, in Wuhan, China. It was first confirmed in sub-Saharan Africa in Nigeria on 27 February 2020 and has since spread quickly to all sub-Saharan African countries, causing more than 111,309 confirmed cases and 2,498 deaths as of 03 June 2020. The lessons learned during the recent Ebola virus disease (EVD) outbreaks in some sub-Saharan African countries were expected to shape and influence the region's responses to COVID-19 pandemic. However, some of the challenges associated with the management of the EVD outbreaks persist and create obstacles for the effective management of the COVID-19 pandemic. This article describes the commonalities between the EVD epidemics and COVID-19 pandemic, with a view to draw on lessons learned to effectively tackle the ongoing pandemic. Key successes, failures and lessons learned from previous EVD outbreaks are discussed. Recommendations on how these lessons can be translated to strengthen the COVID-19 response in sub-Saharan Africa are provided.

Hepatitis B Core-related Antigen: An Alternative to Hepatitis B Virus DNA to Assess Treatment Eligibility in Africa

BACKGROUND

To eliminate hepatitis B virus (HBV) infection, it is essential to scale up testing and treatment. However, conventional tools to assess treatment eligibility, particularly nucleic acid testing (NAT) to quantify HBV DNA, are hardly available and affordable in resource-limited countries. We therefore assessed the performance of a novel immunoassay, hepatitis B core-related antigen (HBcrAg), as an inexpensive (US$ <15/assay) alternative to NAT to diagnose clinically important HBV DNA thresholds (≥2000, ≥20 000, and ≥200 000 IU/mL) and to select patients for antiviral therapy in Africa.

METHODS

Using a well-characterized cohort of treatment-naive patients with chronic HBV infection in The Gambia, we evaluated the accuracy of serum HBcrAg to diagnose HBV DNA levels and to indicate treatment eligibility determined by the American Association for the Study of Liver Diseases, based on reference tests (HBV DNA, hepatitis B e antigen, alanine aminotransferase, liver histopathology, and/or FibroScan).

RESULTS

A total of 284 treatment-naive patients were included in the analysis. The area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity of serum HBcrAg were 0.88 (95% confidence interval [CI], .82-.93), 83.3%, and 83.9%, respectively, to diagnose HBV DNA ≥2000 IU/mL; and 0.94 (95% CI, .88-.99), 91.4%, and 93.2% for ≥200 000 IU/mL. A simplified treatment algorithm using HBcrAg without HBV DNA showed high AUROC (0.91 [95% CI, .88-.95]) with a sensitivity of 96.6% and specificity of 85.8%.

CONCLUSIONS

HBcrAg might be an accurate alternative to HBV DNA quantification as a simple and inexpensive tool to identify HBV-infected patients in need of antiviral therapy in low- and middle-income countries.

[Prevention of liver fibrosis and liver cancer linked to hepatitis B virus in Africa: the Prolifica study]

Despite the existence of an effective vaccine, HBV infects 257 million people worldwide and is the cause of the majority of HCC. With an annual mortality rate of 887 000 patients in 2015, this cancer is the second deadliest. Low-income countries such as ones in sub-Saharan Africa are the most at risk due to the limited access to healthcare. To overcome this and born from an international research collaboration within an EU project, the Prolifica study aimed at evaluating a screen-and-treat program to prevent HBV complications, and more particularly HCC. Based on communities, facilities and hospitals HBsAg+ detection, the study lasted from 2011 to 2016. From the "cost effectiveness" feasibility of such a program to the development of simple scores for antiviral treatment, Prolifica uncovered data of crucial importance in a region with low HBV infection awareness, transmissions modes and prevention means which could have impacts on public health policies.

Development of a simple score based on HBeAg and ALT for selecting patients for HBV treatment in Africa

BACKGROUND & AIMS

To eliminate hepatitis B virus (HBV) infection, it is essential to scale up antiviral treatment through decentralized services. However, access to the conventional tools to assess treatment eligibility (liver biopsy/Fibroscan®/HBV DNA) is limited and not affordable in resource-limited countries. We developed and validated a simple score to easily identify patients in need of HBV treatment in Africa.

METHODS

As a reference, we used treatment eligibility determined by the European Association for the Study of the Liver based on alanine aminotransferase (ALT), liver histology and/or Fibroscan and HBV DNA. We derived a score indicating treatment eligibility by a stepwise logistic regression using a cohort of chronic HBV infection in The Gambia (n = 804). We subsequently validated the score in an external cohort of HBV-infected Africans from Senegal, Burkina Faso, and Europe (n = 327).

RESULTS

Out of several parameters, two remained in the final model, namely HBV e antigen (HBeAg) and ALT level, constituting a simple score (treatment eligibility in Africa for the hepatitis B virus: TREAT-B). The score demonstrated a high area under the receiver operating characteristic curve (0.85, 95% CI 0.79-0.91) in the validation set. The score of 2 and above (HBeAg-positive and ALT ≥20 U/L or HBeAg-negative and ALT ≥40 U/L) had a sensitivity and specificity for treatment eligibility of 85% and 77%, respectively. The sensitivity and specificity of the World Health Organization criteria based on the aspartate aminotransferase-to-platelet ratio index (APRI) and ALT were 90% and 40%, respectively.

CONCLUSIONS

A simple score based on HBeAg and ALT had a high diagnostic accuracy for the selection of patients for HBV treatment. This score could be useful in African settings.

LAY SUMMARY

Limited access to the diagnostic tools used to assess treatment eligibility (liver biopsy/Fibroscan/hepatitis B virus DNA) has been an obstacle to the scale up of hepatitis B treatment programs in low- and middle-income countries. Using the data from African patients with chronic HBV infection, we developed and validated a new simple diagnostic score for treatment eligibility, which only consists of hepatitis B virus e antigen and alanine aminotransferase level. The diagnostic accuracy of the score for selecting patients for HBV treatment was high and could be useful in African settings.

Aiming at the Global Elimination of Viral Hepatitis: Challenges Along the Care Continuum

A recent international workshop, organized by the authors, analyzed the obstacles facing the ambitious goal of eliminating viral hepatitis globally. We identified several policy areas critical to reaching elimination targets. These include providing hepatitis B birth-dose vaccination to all infants within 24 hours of birth, preventing the transmission of blood-borne viruses through the expansion of national hemovigilance schemes, implementing the lessons learned from the HIV epidemic regarding safe medical practices to eliminate iatrogenic infection, adopting point-of-care testing to improve coverage of diagnosis, and providing free or affordable hepatitis C treatment to all. We introduce Egypt as a case study for rapid testing and treatment scale-up: this country offers valuable insights to policy makers internationally, not only regarding how hepatitis C interventions can be expeditiously scaled-up, but also as a guide for how to tackle the problems encountered with such ambitious testing and treatment programs.

Hepatitis B testing and treatment in HIV patients in The Gambia-Compliance with international guidelines and clinical outcomes

BACKGROUND

Compliance with WHO guidelines on HBV screening and treatment in HIV-coinfected patients is often challenging in resource limited countries and has been poorly assessed in sub-Saharan Africa.

METHODS

Between 2015 and 2016, we assessed physician's compliance with WHO guidelines on HIV-HBV coinfection in the largest HIV clinic in The Gambia, and the hepatic outcomes in HIV-HBV coinfected patients as compared to randomly selected HIV-monoinfected controls.

RESULTS

870 HIV-infected patients regularly seen in this clinic agreed to participate in our study. Only 187 (21.5%, 95% CI 18.8-24.3) had previously been screened for HBsAg, 23 (12.3%, 95% CI 8.0-17.9) were positive of whom none had liver assessment and only 6 (26.1%) had received Tenofovir. Our HBV testing intervention was accepted by all participants and found 94/870 (10.8%, 95% CI 8.8-13.1) positive, 78 of whom underwent full liver assessment along with 40 HBsAg-negative controls. At the time of liver assessment, 61/78 (78.2%) HIV-HBV coinfected patients received ART with 7 (11.5%) on Tenofovir and 54 (88.5%) on Lamivudine alone. HIV-HBV coinfected patients had higher APRI score compared to controls (0.58 vs 0.42, p = 0.002). HBV DNA was detectable in 52/53 (98.1%) coinfected patients with 14/53 (26.4%) having HBV DNA >20,000 IU/L. 10/12 (83.3%) had at least one detectable 3TC-associated HBV resistance, which tended to be associated with increase in liver fibrosis after adjusting for age and sex (p = 0.05).

CONCLUSIONS

Compliance with HBV testing and treatment guidelines is poor in this Gambian HIV programme putting coinfected patients at risk of liver complications. However, the excellent uptake of HBV screening and linkage to care in our study suggests feasible improvements.

Natural history of chronic HBV infection in West Africa: a longitudinal population-based study from The Gambia

BACKGROUND

The natural history of chronic HBV infection in sub-Saharan Africa is unknown. Data are required to inform WHO guidelines that are currently based on studies in Europe and Asia.

METHODS

Between 1974 and 2008, serosurveys were repeated in two Gambian villages, and an open cohort of treatment-naive chronic HBV carriers was recruited. Participants were followed to estimate the rates of hepatitis B e (HBeAg) and surface antigen (HBsAg) clearance and incidence of hepatocellular carcinoma (HCC). In 2012-2013, a comprehensive liver assessment was conducted to estimate the prevalence of severe liver disease.

RESULTS

405 chronic carriers (95% genotype E), recruited at a median age of 10.8 years, were followed for a median length of 28.4 years. Annually, 7.4% (95% CI 6.3% to 8.8%) cleared HBeAg and 1.0% (0.8% to 1.2%) cleared HBsAg. The incidence of HCC was 55.5/100 000 carrier-years (95% CI 24.9 to 123.5). In the 2012-2013 survey (n=301), 5.5% (95% CI 3.4% to 9.0%) had significant liver fibrosis. HBV genotype A (versus E), chronic aflatoxin B1 exposure and an HBsAg-positive mother, a proxy for mother-to-infant transmission, were risk factors for liver fibrosis. A small proportion (16.0%) of chronic carriers were infected via mother-to-infant transmission; however, this population represented a large proportion (63.0%) of the cases requiring antiviral therapy.

CONCLUSIONS

The incidence of HCC among chronic HBV carriers in West Africa was higher than that in Europe but lower than rates in East Asia. High risk of severe liver disease among the few who are infected by their mothers underlines the importance of interrupting perinatal transmission in sub-Saharan Africa.

Implementation of an in-house quantitative real-time polymerase chain reaction method for Hepatitis B virus quantification in West African countries

Hepatitis B virus (HBV) is a major cause of chronic liver disease worldwide. HBV infection is diagnosed by serological tests, while real-time polymerase chain reaction (qRT-PCR) assays are used to quantify viral load, which is a crucial parameter to determine viral replication and to monitor antiviral treatments. However, measuring viral load in resource-limited countries remains nonsystematic, due to the high cost of commercial kits. Here, we describe the development, validation and implementation of a low-cost, in-house qRT-PCR assay to monitor HBV viral load in chronic carriers enrolled in the PROLIFICA programme in the Gambia and Senegal. Over 1500 HBsAg-positive patients, including 210 chronically infected HBV patients, who were given antiviral treatment (tenofovir), were monitored by qRT-PCR using the SYBR Green- and HBV-specific primers. Twenty-four tenofovir-treated patients were followed up and their viral load was tested every 3 months over the 12-month experimental time course. Compared to commercial assays, our in-house assay was shown to be (i) highly reliable, with good intra- and interassay reproducibility over a wide range (45-4.5 × 108 copies mL-1 ), (ii) very similar in the viral loads detected (R2  = .90), (iii) highly sensitive, as it detected loads as low as 30 copies mL-1 (~5 IU mL-1 ), (iv) cheaper (2- to 3-fold), (v) easier to implement and (vi) more rapid. Based on our experience, we recommend this assay as a reliable alternative to commercial assays, for monitoring HBV viraemia in resource-limited, highly endemic countries to reduce the cost and technical obstacles associated with commercial kits.

The gamma-glutamyl transpeptidase to platelet ratio (GPR) predicts significant liver fibrosis and cirrhosis in patients with chronic HBV infection in West Africa

BACKGROUND

Simple and inexpensive non-invasive fibrosis tests are highly needed but have been poorly studied in sub-Saharan Africa.

METHODS

Using liver histology as a gold standard, we developed a novel index using routine laboratory tests to predict significant fibrosis in patients with chronic HBV infection in The Gambia, West Africa. We prospectively assessed the diagnostic accuracy of the novel index, Fibroscan, aspartate transaminase-to-platelet ratio index (APRI), and Fib-4 in Gambian patients with CHB (training set) and also in French and Senegalese CHB cohorts (validation sets).

RESULTS

Of 135 consecutive treatment-naïve patients with CHB who had liver biopsy, 39% had significant fibrosis (Metavir fibrosis stage ≥F2) and 15% had cirrhosis (F4). In multivariable analysis, gamma-glutamyl transpeptidase (GGT) and platelet count were independent predictors of significant fibrosis. Consequently, GGT-to-platelet ratio (GPR) was developed. In The Gambia, the area under the receiver operating characteristic curve (AUROC) of the GPR was significantly higher than that of APRI and Fib-4 to predict ≥F2, ≥F3 and F4. In Senegal, the AUROC of GPR was significantly better than Fib-4 and APRI for ≥F2 (0.73, 95% CI 0.59 to 0.86) and better than Fib-4 and Fibroscan for ≥F3 (0.93, 0.87 to 0.99). In France, the AUROC of GPR to diagnose ≥F2 (0.72, 95% CI 0.59 to 0.85) and F4 (0.87, 0.76 to 0.98) was equivalent to that of APRI and Fib-4.

CONCLUSIONS

The GPR is a more accurate routine laboratory marker than APRI and Fib-4 to stage liver fibrosis in patients with CHB in West Africa. The GPR represents a simple and inexpensive alternative to liver biopsy and Fibroscan in sub-Saharan Africa.

Acceptability and feasibility of a screen-and-treat programme for hepatitis B virus infection in The Gambia: the Prevention of Liver Fibrosis and Cancer in Africa (PROLIFICA) study

BACKGROUND

Despite the introduction of immunisation for hepatitis B virus (HBV) in the 1990s, HBV-related morbidity and mortality remain high in sub-Saharan Africa. Identification and treatment of asymptomatic people with chronic HBV infection should reduce the disease burden. We therefore assessed the feasibility of a screen-and-treat programme for HBV infection in The Gambia, west Africa, and estimated the proportion of HBV-infected people who had significant liver disease in need of treatment.

METHODS

Between Dec 7, 2011, and Jan 24, 2014, individuals living in randomly selected communities in western Gambia were offered hepatitis B surface antigen (HBsAg) screening via a point-of-care test. The test was also offered to potential blood donors attending the central hospital in the capital, Banjul. HBsAg-positive individuals were invited for a comprehensive liver assessment and were offered treatment according to international guidelines. We defined linkage to care as visiting the liver clinic at least once. Eligibility for treatment was judged in accordance with the 2012 European Association for the Study of the Liver guidelines.

FINDINGS

HBsAg screening was accepted by 5980 (weighted estimate 68·9%, 95% CI 65·0-72·4) of 8170 adults from 27 rural and 27 urban communities and 5559 (81·4%, 80·4-82·3) of 6832 blood donors. HBsAg was detected in 495 (8·8%, 7·9-9·7) individuals in communities and 721 (13·0%, 12·1-13·9) blood donors. Prevalence was higher in men (239 [10·5%, 8·9-12·1] of 2328 men vs 256 [7·6%, 6·5-8·7] of 3652 women; p=0·004) and middle-aged participants. Linkage to care was high in the communities, with 402 (81·3%) of 495 HBsAg-positive individuals attending the clinic. However, only 300 (41·6%) of 721 HBsAg-positive people screened at the blood bank linked into care. Of those who attended the clinic, 18 (4·4%, 2·5-7·7) patients from the communities and 29 (9·7%, 6·8-13·6) from the blood bank were eligible for treatment. Male sex was strongly associated with treatment eligibility (odds ratio 4·35, 1·50-12·58; p=0·007).

INTERPRETATION

HBV infection remains highly prevalent in The Gambia. The high coverage of community-based screening, good linkage into care, and the small proportion of HBsAg carriers who need treatment suggest that large-scale screening and treatment programmes are feasible in sub-Saharan Africa.

FUNDING

European Commission (FP7).

Hepatitis E virus infection and acute-on-chronic liver failure in West Africa: a case-control study from The Gambia

BACKGROUND

In sub-Saharan Africa, it is unknown whether hepatitis E virus (HEV) infection is a common precipitating event of acute-on-chronic liver failure (ACLF).

AIMS

To estimate the prevalence of HEV infection in general population and assess whether HEV is a common trigger of ACLF in cirrhotic patients in The Gambia, West Africa.

METHODS

We first conducted an HEV sero-survey in healthy volunteers. We then tested cirrhotic patients with ACLF (cases) and compensated cirrhosis (controls) for anti-HEV IgG as a marker of exposure to HEV, and anti-HEV IgA and HEV RNA as a marker of recent infection. We also described the characteristics and survival of the ACLF cases and controls.

RESULTS

In the healthy volunteers (n = 204), 13.7% (95% CI: 9.6-19.2) were positive for anti-HEV IgG, and none had positive HEV viraemia. After adjusting for age and sex, the following were associated with positive anti-HEV IgG: being a Christian, a farmer, drinking water from wells, handling pigs and eating pork. In 40 cases (median age: 45 years, 72.5% male) and 71 controls (39 years, 74.6% male), ≥70% were infected with hepatitis B virus. Although hepatitis B flare and sepsis were important precipitating events of ACLF, none had marker of acute HEV. ACLF cases had high (70.0%) 28-day mortality.

CONCLUSIONS

Hepatitis E virus infection is endemic in The Gambia, where both faecal-oral route (contaminated water) and zoonotic transmission (pigs/pork meat) may be important. However, acute HEV was not a common cause of acute-on-chronic liver failure in The Gambia.

Ebola: is the response justified?

Ebola virus disease is a viral hemorrhagic fever, first discovered in 1976 in Sudan, where the outbreak infected over 284 people with a 53% case fatality ratio. There have been 34 further epidemics, the current major incident in West Africa having recorded more cases and deaths than all previous outbreaks combined. To date there have been over 27, 000 confirmed, probable and suspected cases and 11,000 reported deaths in Liberia, Guinea and Sierra Leone. With total funding and pledges to help control the outbreak amounting to more than US $2.4 billion, many question how the disease has continued to spread in Sierra Leone and Guinea Conakry, and whether the response to the outbreak has been justified. This article aims to analyze the effectiveness of the responses to the outbreak in terms of economic, social, cultural and, to an extent, political impact. We argue that the response has been justified due to the awareness raised, the infrastructure and staffing improvements, the success in receiving financial aid and the minimal spread to other countries outside the main transmission zone. Despite this, some failures in communication and a slow early response were noted.

Birth order and risk of hepatocellular carcinoma in chronic carriers of hepatitis B virus: a case-control study in The Gambia

BACKGROUND & AIMS

Early age at infection with Hepatitis B virus (HBV) increases the risk of chronic infection. Moreover, early HBV infection may further independently increase the risk of hepatocellular carcinoma (HCC) beyond its effect on chronicity.

METHODS

The distribution of birth order, a proxy for mode and timing of HBV transmission, was compared in The Gambia between hepatitis B surface antigen (HBsAg)-positive HCC cases recruited from hospitals (n = 72) and two HBsAg-positive control groups without HCC: population-based controls from a community HBV screening (n = 392) and hospital-based controls (n = 63).

RESULTS

HCC risk decreased with increasing birth order in the population-based case-control analysis. Using first birth order as the reference, the odds ratios were 0.52 (95% CI: 0.20-1.36), 0.52 (0.17-1.56), 0.57 (0.16-2.05) and 0.14 (0.03-0.64) for second, third, fourth and greater than fourth birth order respectively (P = 0.01). A similar inverse association was observed in the hospital-based case-control comparison (P = 0.04).

CONCLUSIONS

Compared to controls, HCC cases had earlier birth order, a proxy for young maternal age and maternal HBV viraemia at birth. This finding suggests that in chronic HBV carriers perinatal mother-to-infant transmission may increase HCC risk more than horizontal transmission. Providing HBV vaccine within 24 h of birth to interrupt perinatal transmission might reduce the incidence of HCC in The Gambia.

Validation of rapid point-of-care (POC) tests for detection of hepatitis B surface antigen in field and laboratory settings in the Gambia, Western Africa

Hepatitis B virus (HBV) infection is a leading cause of death in sub-Saharan Africa (SSA). Point-of-care tests for hepatitis B surface antigen (HBsAg) could be an ideal tool for a large-scale HBV screening/treatment program in SSA. Using data from the PROLIFICA (Prevention of Liver Fibrosis and Cancer in Africa) program, we conducted a cross-sectional study to assess the diagnostic accuracy of three point-of-care tests (Determine, Vikia, and Espline) for the detection of HBsAg in the field or a laboratory setting in the Gambia. In the field, we used finger-prick whole blood for the Determine and Vikia tests and dried blood spots for the reference standard test (AxSYM HBsAg enzyme-linked immunosorbent assay [ELISA]). In the laboratory we used serum for the Determine, Espline, and reference test (Architect chemiluminescent microparticle immunoassay). Of 773 participants recruited at the community and 227 known chronic HBV carriers (1,000 subjects in total), 293 were positive for HBsAg. The sensitivity and specificity of the Determine test were 88.5% and 100% in the field and 95.3% and 93.3% in the laboratory setting, respectively. The sensitivity and specificity were 90.0% and 99.8% for the Vikia test (in the field) and 93.9% and 94.7% for the Espline test (in the laboratory). There was no evidence that one kit was better than another. Most of the patients with false-negative results (18/19) were classified as inactive chronic carriers. In summary, the three point-of-care tests had acceptable ranges of diagnostic accuracy. These tests may represent accurate, rapid, and inexpensive alternatives to serology testing for the screening of HBV infection at field level in SSA.