Diagnostic performance evaluation of hepatitis B e antigen rapid diagnostic tests in Malawi

Hepatitis B core-related antigen rapid diagnostic test for point-of-care identification of women at high risk of hepatitis B vertical transmission: a multicountry diagnostic accuracy study

BACKGROUND

Timely administration of the hepatitis B virus (HBV) birth dose vaccine, along with identifying high-risk pregnant individuals for antiviral prophylaxis, is essential for the global elimination of vertical transmission of HBV. However, in resource-limited settings, access to HBV DNA testing is scarce, and accurate rapid tests for HBeAg are lacking. We aimed to assess the diagnostic performance of a newly developed hepatitis B core-related antigen (HBcrAg) rapid diagnostic test (RDT) to identify women who are HBsAg-positive and eligible for antiviral prophylaxis.

METHODS

In this multicountry diagnostic accuracy study, we retrospectively validated the HBcrAg-RDT using stored plasma from pregnant women who were HBsAg-positive in cohort studies from Cambodia and Cameroon and prospectively using finger-prick capillary blood from postpartum mothers at rural health centres in Burkina Faso. We estimated the sensitivity and specificity of the HBcrAg-RDT for diagnosing high HBV DNA concentrations (≥200 000 IU/mL) using real-time PCR (rtPCR) as the reference. We compared the diagnostic performance of the HBcrAg-RDT with that of conventional HBeAg assays based on the area under the receiver operating characteristic curve (AUROC).

FINDINGS

In total, plasma samples were available for 1964 participants: 1194 stored plasma samples available for analysis from the Cambodian cohort, 501 stored samples from the Cameroonian cohort, and 269 prospectively collected samples from women in the Burkina Faso cohort. In the pooled population, the mean age was 28·1 years (SD 6·0), and 382 (20·0%) were HBeAg positive. The HBcrAg-RDT showed an overall sensitivity of 93·1% (95% CI 90·5-95·2) and specificity of 94·3% (93·0-95·4). Sensitivity and specificity were 93·4% (90·7-95·5) and 94·4% (92·9-95·6) in the retrospective laboratory-based analyses of samples from Cambodia and Cameroon, and 89·7% (75·8-97·1) and 93·9% (90·0-96·6) in the prospective real-world analysis of samples of HBsAg-positive women from Burkina Faso. The AUROC for HBcrAg-RDT (0·937 [95% CI 0·924-0·950]) in distinguishing high versus low HBV DNA concentrations at the 200 000 IU/mL threshold in the pooled data set was significantly higher than that of HBeAg rapid tests (0·822 [0·798-0·845]; p<0·0001) and similar to laboratory-based HBeAg immunoassays (ELISA and chemiluminescence assay; 0·926 [0·897-0·955]; p=0·72). In Burkina Faso, the median turnaround time for HBV DNA testing was 46 days (IQR 31-72), whereas HBcrAg-RDT provided same-day results for all participants.

INTERPRETATION

HBcrAg-RDT might offer a practical solution for integrating the prevention of vertical transmission of HBV into decentralised antenatal care in resource-limited settings, enabling timely identification and management of pregnant individuals who are at high risk of transmission.

FUNDING

Agence Nationale de Recherches sur le Sida et les Hépatites Virales, Total Foundation, Gilead Sciences, and Japan Society for the Promotion of Science.

TRANSLATION

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

Vertical transmission of hepatitis B virus in the WHO African region: a systematic review and meta-analysis

BACKGROUND

More new infections with hepatitis B virus (HBV) occur annually in the WHO African region than in the rest of the world combined. We did a systematic review and meta-analysis to estimate the prevalence of hepatitis B surface antigen (HBsAg) in pregnant women and vertical transmission events in the region.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, Scopus, Africa Index Medicus, and Africa Journals Online for publications between Jan 1, 1992, and Jan 7, 2024, with no language restrictions. HBsAg prevalence and vertical transmission (HBsAg positivity in children aged 6-12 months) were estimated with the use of binomial mixed models with logit links, stratified by infant vaccination status. We estimated HBsAg prevalence for subregions of Africa and for the WHO African region by weighting by estimated livebirths for each subregion. We estimated transmission events using WHO and UNICEF vaccine coverage data and UN population estimates.

FINDINGS

We included 113 studies reporting on HBsAg prevalence from 190 983 pregnant women and 11 studies reporting on vertical transmission. HBsAg prevalence in women receiving antenatal care in the WHO African region (based on 2014-23 data) was 6·2% (95% CI 5·3-7·2). No relationship between risk of bias and HBsAg prevalence was observed. In 2022, an estimated 172 000 vertical transmission events (95% CI 82 000-383 000) occurred (0·4% of livebirths), a fall from a peak of 339 000 (149 000-634 000; 1·2% of all livebirths) in 2001. Increasing birth dose vaccination coverage to the WHO target of 90% could reduce vertical transmission by 43·7% (95% CI 11·6-78·0) to 97 000 events per year (95% CI 58 000-160 000). Adding maternal antiviral prophylaxis with 90% coverage could reduce transmission by 86·3% (95% CI 78·4-94·6) to 24 000 events per year (95% CI 14 000-39 000; 0·06% of livebirths) and achieve WHO elimination targets.

INTERPRETATION

Vertical transmission is an important contributor to HBV transmission in the WHO African region. Scaling up of hepatitis B birth dose vaccination and antiviral prophylaxis is urgently needed, which could achieve elimination of vertical transmission.

FUNDING

Wellcome Trust.

Production and characterization of monoclonal antibodies against hepatitis B e-antigen and their potential application for development of HBeAg detection ELISA

Despite global vaccination efforts, hepatitis B virus (HBV) infection remains a major health threat, causing over a million deaths annually. Hepatitis B e-antigen (HBeAg) is an indicator of HBV replication and high infectivity. HBeAg is an essential serological marker for monitoring response to treatment and/or determining the stage of chronic HBV infection. Here, we produced a panel of mouse hybridomas secreting monoclonal antibodies (MAbs) to HBeAg by fusing a mouse myeloma cell line with splenocytes from mice immunized with recombinant HBeAg. Anti-HBe MAbs were then characterized by competition ELISA and Western blotting. We designed and optimized an in-house sandwich ELISA using HBeAg-specific rabbit polyclonal and mouse monoclonal antibodies. The diagnostic performance of the assay was then compared to a commercial HBeAg detection ELISA kit using 176 HBeAg[-] and 44 HBeAg[+] serum samples, showing a significant positive correlation (r = 0.8250; P < 0.0001). The in-house ELISA showed reasonable sensitivity (97.56 %) and specificity (99.40 %), with a cut-off value and area under the curve of 0.193 and 0.9884, respectively. Additionally, the assay showed high repeatability, with intra- and inter-assay coefficients of variation of 2.46 % and 11.38 %, respectively. Our designed HBeAg-detecting sandwich ELISA has the potential for use in clinical diagnosis.

Rapid test for hepatitis B core-related antigen to identify people living with hepatitis B having high viral load in Cameroon

This study presents a retrospective assessment of the diagnostic performance of the newly developed hepatitis B core-related antigen rapid diagnostic test (HBcrAg-RDT) in detecting plasma samples with elevated hepatitis B virus (HBV) DNA levels (≥200,000 IU/ml) in Yaoundé, Cameroon. Samples were collected consecutively from treatment-naïve adults living with HBV between January 1, 2021, and June 30, 2023. Analyzing 146 samples from participants with a median age of 36 years, the HBcrAg-RDT exhibited a sensitivity of 97.5% (95% CI: 86.8-99.9) and a specificity of 77.4% (68.2-84.9) when compared to real-time PCR as the reference standard. These findings suggest that HBcrAg-RDT holds promise as a valuable point-of-care tool for diagnosing high HBV DNA levels, particularly in resource-limited settings. Further research will refine its practicality and effectiveness.

Global elimination of HBV: Is it really achievable?

Hepatitis B virus (HBV) infection is a major cause of premature death worldwide. In 2016, the World Health Organization (WHO) called for HBV elimination and set up very ambitious elimination targets. The development of effective vaccines, accurate diagnostic tools and safe antiviral drugs make HBV elimination a realistic goal. However, the most constrained-resource regions, which bear the highest burden of HBV, are facing major challenges in implementing strategies to reduce HBV incidence and mortality. Developing simplified approaches adapted to resource-limited settings and scaling up interventions for the prevention and control of HBV globally are urgently needed. Whether HBV elimination will be achieved in an equitable manner and in a reasonable timeframe remains highly uncertain.

Newer Diagnostic Virological Markers for Hepatitis B Virus Infection

Chronic Hepatitis B (CHB) remains a major public health problem, leading to various complications such as liver fibrosis, cirrhosis, and hepatocellular carcinoma. The existing diagnostic markers for Hepatitis B virus (HBV) are limited in distinguishing different CHB phases and intra-hepatic viral replication activity. In the past few years, several non-invasive potential blood markers that reflect viral intra-hepatic replicative state more accurately have been in progress and are gaining importance. Despite substantial efforts, the clinical utility of these new markers in CHB management is limited and unexplored. Therefore, in this review, we will discuss some of the newer HBV markers, their potential role in the diagnosis and monitoring of CHB patients.

How to cite this article

Agarwal R, Gupta E, Samal J, et al. Newer Diagnostic Virological Markers for Hepatitis B Virus Infection. Euroasian J Hepato-Gastroenterol 2024;14(2):214-220.

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.

Point-of-Care Testing for Hepatitis Viruses: A Growing Need

Viral hepatitis, caused by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV), is a major global public health problem. These viruses cause millions of infections each year, and chronic infections with HBV, HCV, or HDV can lead to severe liver complications; however, they are underdiagnosed. Achieving the World Health Organization's viral hepatitis elimination goals by 2030 will require access to simpler, faster, and less expensive diagnostics. The development and implementation of point-of-care (POC) testing methods that can be performed outside of a laboratory for the diagnosis of viral hepatitis infections is a promising approach to facilitate and expedite WHO's elimination targets. While a few markers of viral hepatitis are already available in POC formats, tests for additional markers or using novel technologies need to be developed and validated for clinical use. Potential methods and uses for the POC testing of antibodies, antigens, and nucleic acids that relate to the diagnosis, monitoring, or surveillance of viral hepatitis infections are discussed here. Unmet needs and areas where additional research is needed are also described.

Evaluation of the Diagnostic Performances of the SD-Bioline®HBeAg Rapid Test Used Routinely for the Management of HBV-Infected Individuals in Burkina Faso

Hepatitis B e antigen (HBeAg) is a marker of wild-type hepatitis B virus replication. In resource-limited countries where access to enzyme-linked immunosorbent assay (ELISA) remains a challenge, rapid diagnostic tests (RDT) constitute a good alternative. The HBeAg status is employed to evaluate eligibility for antiviral therapy and to prevent the transmission of hepatitis B from mother to child (PMTCT). The objective of this study was to assess the diagnostic performance of the SD-Bioline®HBeAg RDT commonly used for detecting HBeAg in laboratories in Burkina Faso. The sample panel used was collected from HBsAg-positive patients received in the laboratory for the detection of HBeAg with the rapid test. The samples were retested for HBeAg using the VIDAS HBe/Anti-HBe enzyme-linked fluorescent assay (ELFA) (Gold standard). Then, the viral load (VL) of HBV DNA was determined using the GENERIC HBV CHARGE VIRLAE kit (GHBV-CV). The diagnostic performances of the SD-Bioline®HBeAg and its agreement with the gold standard were calculated with their 95% confidence intervals. Overall, 340 sera obtained from HBsAg-positive patients were included in this evaluation Compared to the VIDAS HBe/Anti-HBe ELFA test, the sensitivity (Se) and specificity (Sp) of the SD-Bioline®HBeAg test were 33.3% and 97.9%, respectively. The concordance between the two tests was 0.42. Depending on the viral load, the Se and Sp varied from 8.8% and 98.3% for a VL < 2000 IU/mL to 35.5% and 98.4% for a VL > 2,000,000 IU/mL. The results showed a low sensibility of the SD-Bioline®HBeAg RDT test, indicating that its use is inappropriate for the clinical management of HBV-infected patients. They also highlight the urgent need to develop HBeAg rapid tests with better sensitivities.

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.

Impact and cost-effectiveness of hepatitis B virus prophylaxis in pregnancy: a dynamic simulation modelling study

BACKGROUND

In 2020, WHO recommended the addition of peripartum antiviral prophylaxis (PAP) to hepatitis B birth dose vaccination (HepB-BD) and hepatitis B infant vaccination (HepB3) to reduce mother-to-child transmission of hepatitis B virus (HBV) infection in pregnant women who have a marker of high infectivity (ie, HBV DNA ≥200 000 international units per mL or HBeAg-positive). We aimed to evaluate the impact and cost-effectiveness of this recommendation and of a theoretical simplified strategy whereby PAP is given to all pregnant women who are HBsAg-positive without risk stratification.

METHODS

This modelling study used a dynamic simulation model of the HBV epidemic in 110 countries in all WHO regions, structured by age, sex, and country. We assessed three strategies of scaling up PAP for pregnant women: PAP for those with high viral load (PAP-VL); PAP for those who are HBeAg-positive (PAP-HBeAg); and PAP for all pregnant women who are HBsAg-positive (PAP-universal), in comparison with neonatal vaccination alone (HepB-BD). We investigated how different diagnostic and antiviral drug costs affected the cost-effectiveness of the strategies evaluated. Using a health-care provider perspective, we calculated incremental cost-effectiveness ratios in cost (US$) per disability-adjusted life-year (DALY) averted in each country's population and compared these with country-specific cost-effectiveness thresholds. We also calculated new neonatal infections averted for each of the strategies.

FINDINGS

Adding PAP-VL to HepB-BD could avert around 1·1 million (95% uncertainty interval 1·0 million-1·2 million) new neonatal infections by 2030 and around 3·2 million (95% uncertainty interval 3·0 million-3·4 million) new neonatal infections and approximately 8·8 million (7·8 million-9·7 million) DALYs by 2100 across all the countries modelled. This strategy would probably be cost-effective up to 2100 in 28 (26%) of 106 countries analysed (which included some of the countries that have the greatest HBV burden) if costs are as currently expected to be, and in 74 (70%) countries if diagnostic and monitoring costs were lowered (by about 60-75%). The relative cost-effectiveness of PAP-VL and PAP-HBeAg was finely balanced and depended on the respective diagnostic and monitoring costs. The PAP-universal strategy could be more cost-effective than either of these strategies in most countries, but the use of antiviral treatment could be five times as high than with PAP-VL.

INTERPRETATION

PAP can provide substantial health benefits, and, although the current approach might already be cost-effective in some high-burden settings, decreased diagnostic costs would probably be needed for PAP to be cost-effective in most countries. Therefore, careful consideration needs to be given about how such a strategy is implemented, and securing reduced costs for diagnostics should be a priority. The theoretical strategy of offering PAP to all women who are HBsAg-positive (eg, if diagnostic tests to identify mothers at risk of transmission are not available) could be a cost-effective alternative, depending on prevailing costs of diagnostics and antiviral therapy.

FUNDING

UK Medical Research Council, UK National Institute for Health and Care Research, and the Vaccine Impact Modelling Consortium.

Systematic review and individual-patient-data meta-analysis of non-invasive fibrosis markers for chronic hepatitis B in Africa

In sub-Saharan Africa, simple biomarkers of liver fibrosis are needed to scale-up hepatitis B treatment. We conducted an individual participant data meta-analysis of 3,548 chronic hepatitis B patients living in eight sub-Saharan African countries to assess the World Health Organization-recommended aspartate aminotransferase-to-platelet ratio index and two other fibrosis biomarkers using a Bayesian bivariate model. Transient elastography was used as a reference test with liver stiffness measurement thresholds at 7.9 and 12.2kPa indicating significant fibrosis and cirrhosis, respectively. At the World Health Organization-recommended cirrhosis threshold (>2.0), aspartate aminotransferase-to-platelet ratio index had sensitivity (95% credible interval) of only 16.5% (12.5-20.5). We identified an optimised aspartate aminotransferase-to-platelet ratio index rule-in threshold (>0.65) for liver stiffness measurement >12.2kPa with sensitivity and specificity of 56.2% (50.5-62.2) and 90.0% (89.0-91.0), and an optimised rule-out threshold (<0.36) with sensitivity and specificity of 80.6% (76.1-85.1) and 64.3% (62.8-65.8). Here we show that the World Health Organization-recommended aspartate aminotransferase-to-platelet ratio index threshold is inappropriately high in sub-Saharan Africa; improved rule-in and rule-out thresholds can optimise treatment recommendations in this setting.

Assessment and validation of the TREAT-B score to assess the treatment eligibility of patients with chronic hepatitis B virus infection

Background and aims

Access to Hepatitis B virus (HBV) DNA testing to determine treatment eligibility is limited in low-income countries. Therefore, this study aimed to assess and validate the TREAT-B score proposed as the treatment threshold in an Asian cohort in determining the HBV treatment eligibility.

Methods

A retrospective analysis was conducted on consecutive patients with treatment-naïve chronic HBV mono-infection who visited the liver clinic at Chulalongkorn University Hospital, Bangkok, Thailand, from 2016 to 2020. The 2018 American Association for the Study of Liver Diseases guideline was the reference standard.

Results

Overall, 825 patients with chronic HBV infection were enrolled, comprising 409 (50.4%) males, with a median age of 50 (38–58) years. Of these, 216 (26.2%), 565 (68.5%), and 377 (45.7%) were eligible for treatment based on the AASLD, TREAT-B score, and simplified WHO criteria, respectively. The area under the receiver operating characteristics curve (AUROC) of the TREAT-B ≥ 2 was better than the simplified WHO criteria (0.69 vs. 0.62, p = 0.006) for selecting patients eligible for antiviral therapy. The sensitivity and specificity of the TREAT-B ≥ 2 were 96.3% and 41.4%, respectively. Applying the TREAT-B ≥ 3 improved the specificity (89.0%) and AUROC (0.80, 95% CI 0.76–0.84, but reduced the sensitivity (70.8%) for selecting eligible patients for HBV therapy.

Conclusions

In resource-constrained countries where HBV DNA is unavailable, the TREAT-B score is an alternative criteria for indicating treatment eligibility. The TREAT-B score of ≥3 is highly accurate and may minimize the number of patients unnecessarily treated in Asian HBV patients.

Enduring Challenges despite Progress in Preventing Mother-to-Child Transmission of Hepatitis B Virus in Angola

Sub-Saharan Africa has one of the highest rates of hepatitis B virus (HBV) infection globally, with an incidence of 1.5 million and 0.8 million yearly deaths, which drives synergistic efforts towards its elimination. To assess the risk of mother-to-child transmission of HBV infection, a cross-sectional study was conducted on 1012 pregnant women in Angola to investigate HBV serological and molecular profiles. The prevalence of HBV was 8.7% (n = 88), with hepatitis B core IgM antibody (anti-HBc IgM) positivity identified in 12.8%, hepatitis B "e" antigen (HBeAg) positivity in 30%, and HBV DNA ≥ 200,000 IU/mL in 28.2%. Family tracking studied 44 children, of which 11 (25%) received at least two doses of the hepatitis B vaccine. HBV was detected in 10/44 (22.7%) children, with vaccination reported in one infected child. Further testing identified anti-HBc IgM positivity in 3/10 (30%), HBeAg positivity in 55%, and both seromarkers in 20%. The results revealed the importance of antenatal HBV screening, antiviral prophylaxis for mothers with high viral loads or HBeAg positivity, and timely first-dose hepatitis B vaccines in newborns. Anti-HBc IgM positivity among pregnant women and children highlights prophylactic measures worth considering, including antenatal hepatitis B vaccination and catch-up vaccination to young children.