A non-randomized vaccine effectiveness trial of accelerated infant hepatitis B immunization schedules with a first dose at birth or age 6 weeks in Côte d’Ivoire. Vaccine. 2008;26:2753-2761. [PMID: 18436354 DOI: 10.1016/j.vaccine.2008.03.018]

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.

Weak Adoption and Performance of Hepatitis B Birth-Dose Vaccination Programs in Africa: Time to Consider Systems Complexity?-A Scoping Review

The persistent burden of chronic hepatitis B among ≤5-year-old children in Africa suggests missed opportunities for controlling mother-to-child transmission (MTCT) of the hepatitis B virus (HBV). This scoping review maps the evidence base on the risk of HBV MTCT, the status of HBV MTCT mitigation strategies including hepatitis B birth-dose vaccination, and the role of systems complexity on the suboptimal adoption and performance of hepatitis B birth-dose vaccination programs in Africa. Overall, 88 peer-reviewed and grey literature sources published between 2000-2022 were included in this review. The growing evidence base consistently argues for a heightened risk of HBV MTCT amidst the HIV co-epidemic in the region. Without universal HBV screening programs integrated within broader antenatal care services, current selective hepatitis B birth-dose vaccination is unlikely to effectively interrupt HBV MTCT. We underscore critical health systems-related barriers to universal adoption and optimal performance of hepatitis B birth-dose vaccination programs in the region. To better conceptualize the role of complexity and system-wide effects on the observed performance of the program, we propose an adapted systems-based logic model. Ultimately, exploring contextualized complex systems approaches to scaling-up universal hepatitis B birth-dose vaccination programs should form an integral part of the regional research agenda.

Hepatitis B prevention and treatment needs in women in Senegal (ANRS 12356 AmBASS survey)

BACKGROUND

Although mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is prevalent in West Africa, epidemiological data on HBV infection in women remain scarce. We studied i) hepatitis B surface antigen (HBsAg) prevalence and its correlates, ii) HBV screening history and serological status awareness, iii) MTCT risk and treatment needs in Senegalese women.

METHODS

A cross-sectional population-based serosurvey for HBsAg positivity was conducted in 2018-2019 in the rural area of Niakhar (Fatick region, Senegal). Participants were offered home-based HBV screening and answered face-to-face questionnaires. HBsAg-positive participants underwent clinical and biological assessments. Data were weighted and calibrated to be representative of the area's population. Logistic regression models helped identify factors associated with HBsAg-positivity in adult women (> 15 years old).

RESULTS

HBsAg prevalence in adult women was 9.2% [95% confidence interval: 7.0-11.4]. Factors associated with HBsAg-positivity were being 15-49 years old (ref: ≥ 50), living in a household with > 2 other HBsAg-positive members, and knowing someone with liver disease. Only 1.6% of women had already been tested for HBV; no one who tested HBsAg positive was already aware of their serological status. In women 15-49 years old, 5% risked MTCT and none were eligible for long-term antiviral treatment.

CONCLUSIONS

Adult women have a high HBsAg prevalence but a low MTCT risk. Low rates of HBV screening and serological status awareness argue for the adoption of systematic screening during pregnancy using free and rapid diagnostic tests. Additionally, screening household members of HBsAg-positive women may greatly improve the cascade of care in rural Senegal.

TRIAL REGISTRATION

ClinicalTrials.gov identifier (NCT number): NCT03215732.

Risk of early horizontal transmission of hepatitis B virus in children of uninfected mothers in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Sub-Saharan Africa is highly endemic for hepatitis B virus (HBV); historically, most people were exposed during childhood through vertical or horizontal transmission. Although all African countries now provide a three-dose infant hepatitis B vaccination starting at age 6-8 weeks, only a third of African countries have introduced birth dose (HepB-BD) vaccine. Adding HepB-BD is fundamental to prevent vertical transmission, but its effectiveness in preventing horizontal transmission, compared with the three-dose infant vaccination alone, is unknown. We aimed to estimate the risk of early horizontal transmission in children of hepatitis B surface antigen (HBsAg)-negative mothers in sub-Saharan Africa stratified according to the vaccination schedule.

METHODS

In this systematic review and meta-analysis we searched MEDLINE, Global Health, Embase, African Index Medicus and African Journals Online from their inception to Oct 24, 2022, for studies reporting HBsAg or HBV DNA, or both, in children (aged 0-5 years) of HBsAg-negative mothers. We excluded studies if children were only tested at birth. Two reviewers independently screened the titles and abstracts of all articles and data were extracted using a standardised pre-piloted data extraction sheet, and authors were contacted if any important information was missing. The primary outcome was the risk of HBV infection in children of HBsAg-negative mothers, stratified by vaccination schedule (no vaccination, first dose at 6-8 weeks, or first dose at birth). We pooled the child risks of HBsAg or HBV DNA-positivity from the age of 0 years to 5 years via a random-effect meta-analysis using a generalised linear mixed model. The study was registered on PROSPERO, CRD42021236203.

FINDINGS

Of 8856 articles identified, 27 studies evaluating 10 003 children of HBsAg-negative mothers were included. The pooled risks of infection were 6·16% (95% CI 3·05-12·04; 155/1407) in the no vaccination group, 0·21% (0·04-1·15; 10/3425) in children who received their first dose at 6-8 weeks, and 0·05% (0·00-1·32; 3/2902) in children who received their first dose at birth. The difference was not statistically significant in children who received their first dose at 6-8 weeks and children who received their first dose at birth after adjusting for the study period, region, and maternal HIV status (test of moderators p=0·37).

INTERPRETATION

In children of HBsAg-negative mothers, the risk of infection might be minimal even with the vaccination starting at 6-8 weeks, without clear additional benefit from HepB-BD. When births take place at home and timely administration of HepB-BD is challenging, antenatal HBsAg screening and selective HepB-BD might allow efficient allocation of resources to mother and child pairs at high risk compared with universal HepB-BD.

FUNDING

None.

TRANSLATION

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

Hepatitis B Virus in West African Children: Systematic Review and Meta-Analysis of HIV and Other Factors Associated with Hepatitis B Infection

While Hepatitis B virus (HBV) and the human immunodeficiency virus (HIV) are endemic in West Africa, the prevalence of HBV/HIV coinfection and their associated risk factors in children remains unclear. In this review, we sought to assess HBsAg seroprevalence among 0- to 16-year-olds with and without HIV in West African countries and the risk factors associated with HBV infection in this population. Research articles between 2000 and 2021 that reported the prevalence of HBV and associated risk factors in children in West Africa were retrieved from the literature using the Africa Journals Online (AJOL), PubMed, Google Scholar, and Web of Science databases as search tools. StatsDirect, a statistical software, was used to perform a meta-analysis of the retained studies. HBV prevalence and heterogeneity were then assessed with a 95% confidence interval (CI). Publication bias was evaluated using funnel plot asymmetry and Egger's test. Twenty-seven articles conducted across seven West African countries were included in this review. HBV prevalence among persons aged 0 to 16 years was 5%, based on the random analysis, given the great heterogeneity of the studies. By country, the highest prevalence was observed in Benin (10%), followed by Nigeria (7%), and Ivory Coast (5%), with Togo (1%) having the lowest. HBV prevalence in an HIV-infected population of children was (9%). Vaccinated children had lower HBV prevalence (2%) than unvaccinated children (6%). HBV prevalence with a defined risk factor such as HIV co-infection, maternal HBsAg positivity, undergoing surgery, scarification, or being unvaccinated ranged from 3-9%. The study highlights the need to reinforce vaccination of newborns, screening for HBV, and HBV prophylaxis among pregnant women in Africa, particularly in West Africa, to achieve the WHO goal of HBV elimination, particularly in children.

Prospective cohort study of prevention of mother to child transmission of hepatitis B infection and 9 months follow-up of hepatitis B-exposed infants at Ile-Ife, Nigeria

OBJECTIVES

Eliminating mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is central to WHO's target of reducing hepatitis B infection in children to <0.1% by 2030. While Nigeria accounts for 8.3% of the global burden, interventional studies on prevention of MTCT of HBV are hardly available. This study aimed to assess the impact of prevention of MTCT interventions on vertical transmission of HBV among pregnant women in Nigeria.

DESIGN

A prospective cohort study.

SETTING

A University Teaching Hospitals Complex in Nigeria between 2015 and 2021.

PARTICIPANTS

10 866 pregnant women and their pre-existing children.

INTERVENTIONS

Eligible pregnant women were screened for HBsAg using chromatographic immunoassay (Micropoint, USA). HbsAg-positive women had HBV serological assay done and their pre-existing children were screened. Women with HBV DNA ≥2 00 000 IU/mL and those positive for hepatitis B e-antigen (HBeAg) had 300 mg/day of Tenofovir Disoproxil Fumarate (TDF) in the third trimester. The newborns had hepatitis B vaccines and HB immunoglobulin (HBIG) administered, followed by testing for HBsAg at 9 months postnatally.

PRIMARY OUTCOME MEASURES

Prevalence of chronic hepatitis B infection in pregnancy, and the incidence of MTCT of HBV.

RESULTS

Overall, 395 women had chronic HBV infection, giving a prevalence of 3.64%. Their mean age was 31.51±5.71 years, with a median parity of 1.2. Thirteen women (5.2%) were positive for HBeAg, seven (3.1%) of the 225 pre-existing hepatitis B-exposed children were HbsAg positive and 17 women had prenatal TDF. Overall, 376 women completed the study, with mean birth weight of 3.21±1.86 kg and perinatal mortality rate of 29.2/1000 births. Hepatitis Bvaccine-HBIG combination was administered to 260 newborns, while the others had hepatitis B vaccine alone. All the children tested negative to the HbsAg at 9 months.

CONCLUSION

Eliminating MTCT of HBV infection through validated protocols in low and middle income countries with the highest burden of chronic HBV infections is feasible. National scale-up of such protocols is recommended.

Drastic sex-dependent etiological distribution in severe liver diseases from Gabon

Chronic liver diseases still represent a worrying public health issue in Sub-Saharan Africa. In this region, emphasis is generally made on hepatocellular carcinoma (HCC) albeit liver cirrhosis (LC) is also responsible for an important death toll. Very few studies have compared the presentation and etiologies of cancer and cirrhosis of the liver in Middle Africa. We conducted a comparative retrospective analysis of 74 and 134 cases of patients with HCC and LC treated in Libreville, Gabon. Viral or lifestyle risk factors, clinical symptoms, and biological features were compared. We observed that ages of diagnosis were 53.2 ± 15.7 years and 48.6 ± 18.6 years for HCC and LC with remarkably low M:F sex ratios (1.3–1.8). Ethanol consumption was highly prevalent in both disease types (65.0%–70.0%). Chronic viral infections with hepatitis B (HBV) or C (HCV) virus were also widespread with slight domination of the former in both diseases (43.4% vs. 34.3%, and 35.9% vs. 28.5%). Patients with HCC were presenting very late with a mean diameter of the main nodule of 84 ± 50 mm and a multifocal pattern in 72.7% of cases. HCC developed on a cirrhotic liver in 91.7% of cases. Serum AFP was frankly elevated (>400 ng/ml) in only 35.8% of HCC cases. The most striking feature of the HCC series was the contrasted contribution of distinct pathogenic etiologies involving sex, viral, metabolic, and toxic factors. A frequently dysmetabolic condition synergizing with hepatitis C (anti-HCV, 73.8% vs 22.7%, p < 0.0001) in females and a male cancer promoted by recreational toxicants and chronic hepatitis B (HBsAg, 83.5% vs 35.9%, p < 0.0001) were observed. Men with HCC were considerably younger than women (46.8 ± 14.5 years vs. 62.2 ± 12.2 years, p < 0.0001). Further studies are now warranted to identify routes of HCV transmission and if they are still fueling reservoirs of future patients. Public policies to prevent alcohol-related harm have also to be urgently implemented in Gabon.

Screening for Hepatitis B in partners and children of women positive for surface antigen, Burkina Faso

Objective

To evaluate the implementation of a screening strategy for the partners and children of pregnant women with hepatitis B virus (HBV) attending antenatal care.

Methods

We identified pregnant women positive for HBV surface antigen (HBsAg) at antenatal consultation in Ouagadougou, Burkina Faso. At post-test counselling, women were advised to disclose their HBV status to partners and to encourage their partner and children to be screened for HBsAg. We used multivariable logistic regression to explore factors associated with uptake of screening and HBsAg positivity among family members.

Findings

Of 1000 HBsAg-positive women, 436/1000 partners and 215/1281 children were screened. HBsAg was detected in 55 (12.6%) partners and 24 (11.2%) children. After adjusting for confounders, uptake of screening was higher in partners who were married, who attended the woman's first post-test consultation and to whom the woman had disclosed her HBV status. In children, HBsAg positivity was associated with being born before the introduction of infant hepatitis B vaccination in Burkina Faso (not significant in the multivariable analysis), having a mother positive for HBV e-antigen (adjusted OR: 8.57; 95% CI: 2.49-29.48) or having a mother with HBV DNA level ≥ 200 000 IU/mL (OR: 6.83; 95% CI: 1.61-29.00).

Conclusion

In low-income countries, the antenatal consultation provides a cost-effective opportunity to identify HBV-infected household contacts and link them to care. Children born before the introduction of infant hepatitis B vaccination and whose mother has higher viral load or infectivity should be a priority for testing and linkage to care.

Cost-effectiveness of adding a birth dose of hepatitis B vaccine in the Dafra district of the Hauts-Bassins Region in Burkina Faso (NéoVac Study)

BACKGROUND

The World Health Organization (WHO) recommends a first hepatitis B vaccine dose within 24 h of birth (HepB-BD) to prevent mother-to-child transmission. Evidence for this strategy's economic value in Africa is limited. We assessed the costs and cost-effectiveness of adding HepB-BD to the current three-dose pentavalent schedule (HepB3) in the Dafra district of the Hauts-Bassins Region in Burkina Faso.

METHODS

Using a decision tree combined with a Markov model, we estimated the expected number of life-years (LY) and disability-adjusted life-years (DALYs) saved, incremental costs, and incremental cost-effectiveness ratios (ICER) of HepB-BD + HepB3 versus HepB3 alone in Dafra's 2017 birth cohort (n = 11,462). Institutional delivery rates, vaccine coverage, and vaccination costs from a health system perspective were estimated from field-collected data. We estimated the effectiveness of HepB-BD, age-specific transition probabilities, and horizontal transmission risks using data from previous African studies. Costs and health outcomes were discounted at an annual rate of 3%. We conducted one-way and probabilistic sensitivity analyses to assess uncertainty.

RESULTS

In the base-case analysis without discounting, HepB-BD + HepB3 yielded a net cost saving of US$18,979 and saved 163 DALYs compared with HepB3 alone. With discounting, HepB-BD + HepB3 compared with HepB3 resulted in an incremental cost of US$554 and 31 DALYs averted, translating into an ICER of US$18/DALY averted. In one-way sensitivity analyses, HepB-BD + HepB3 remained cost-effective (at the cost-effectiveness threshold of US$671 i.e. the Burkina Faso per-capita gross domestic product) for all parameter changes. However, results were very sensitive to variations in HepB-BD unit cost per vaccinated neonate and perinatal transmission risk in mothers carrying the hepatitis B e antigen. The probabilities of HepB-BD + HepB3 being cost-effective were 71.7% and 86.7%, at the cost-effectiveness thresholds of US$335 and US$671, respectively.

CONCLUSION

Introducing HepB-BD in Burkina Faso is likely to be cost-effective.

Impact of Introducing Hepatitis B Birth Dose Vaccines into the Infant Immunization Program in Burkina Faso: Study Protocol for a Stepped Wedge Cluster Randomized Trial (NéoVac Study)

To achieve global hepatitis elimination by 2030, it is critical to prevent the mother-to-child transmission (MTCT) of hepatitis B virus (HBV). Since 2009, the WHO has recommended administering hepatitis B vaccine to all neonates within 24 h of birth to prevent MTCT. However, many countries in sub-Saharan Africa only provide hepatitis B immunization at the age of 6, 10, and 14 weeks or 8, 12, and 16 weeks using a combined vaccine. To accelerate the introduction of the hepatitis B birth dose vaccine (HepB-BD) into sub-Saharan Africa, it is critical to establish to what extent the addition of HepB-BD can further reduce HBV transmission in areas where three-dose infant vaccination has been implemented. We therefore designed a study to evaluate the impact, acceptability, and cost-effectiveness of incorporating the HepB-BD into the routine immunization program in a real-life field condition in Burkina Faso, where the hepatitis B vaccination is currently scheduled at 8-12-16 weeks. Through a multidisciplinary approach combining epidemiology, anthropology, and health economics, the Neonatal Vaccination against Hepatitis B in Africa (NéoVac) study conducts a pragmatic stepped wedge cluster randomized controlled trial in rural areas of the Hauts-Bassins Region. The study was registered in ClinicalTrials.gov (identifier: NCT04029454). A health center is designated as a cluster, and the introduction of HepB-BD will be rolled out sequentially in 24 centers. Following an initial period in which no health center administers HepB-BD, one center will be randomly allocated to incorporate HepB-BD. Then, at a regular interval, another center will be randomized to cross from the control to the intervention period, until all 24 centers integrate HepB-BD. Pregnant women attending antenatal care will be systematically invited to participate. Infants born during the control period will follow the conventional immunization schedule (8-12-16 weeks), while those born in the interventional period will receive HepB-BD in addition to the routine vaccines (0-8-12-16 weeks). The primary outcome, the proportion of hepatitis B surface antigen (HBsAg) positivity in infants aged at 9 months, will be compared between children born before and after HepB-BD introduction. The study will generate data that may assist governments and stakeholders in sub-Saharan Africa to make evidence-based decisions about whether to add HepB-BD into the national immunization programs.

Tenofovir disoproxil fumarate in pregnancy for prevention of mother to child transmission of hepatitis B in a rural setting on the Thailand-Myanmar border: a cost-effectiveness analysis

BACKGROUND

Hepatitis B Virus (HBV) is transmitted from mother to child which can be prevented via birth dose vaccine combined with three follow up hepatitis B vaccines, hepatitis B immunoglobulins (HBIG), and maternal antiviral treatment with Tenofovir Disoproxil Fumarate (TDF). This study evaluates the cost effectiveness of six strategies to prevent perinatal HBV transmission in a resource limited setting (RLS) on the Thailand-Myanmar border.

METHODS

The cost effectiveness of six strategies was tested by a decision tree model in R. All strategies included birth and follow up vaccinations and compared cost per infection averted against two willingness to pay thresholds: one-half and one gross domestic product (GDP) per capita. Strategies were: 1) Vaccine only, 2) HBIG after rapid diagnostic test (RDT): infants born to HBsAg+ are given HBIG, 3) TDF after RDT: HBsAg+ women are given TDF, 4) TDF after HBeAg test: HBeAg+ women are given TDF, 5) TDF after high HBV DNA: women with HBV DNA > 200,000 are given TDF, 6) HBIG & TDF after high HBV DNA: women with HBV DNA > 200,000 are given TDF and their infants are given HBIG. One-way and probabilistic sensitivity analyses were conducted on the cost-effective strategies.

RESULTS

Vaccine only was the least costly option with TDF after HBeAg test strategy as the only cost-effective alternative. TDF after HBeAg test had an incremental cost-effectiveness ratio of US$1062; which would not be considered cost-effective with the lower threshold of one-half GDP per capita. The one-way sensitivity analysis demonstrated that the results were reasonably robust to changes in single parameter values. The PSA showed that TDF after HBeAg test had an 84% likelihood of being cost effective at a willingness to pay threshold of one GDP per capita per infection averted.

CONCLUSIONS

We found that TDF after HBeAg test has the potential to be cost-effective if TDF proves effective locally to prevent perinatal HBV transmission. The cost of TDF treatment and reliability of the RDT could be barriers to implementing this strategy. While TDF after RDT may be a more feasible strategy to implement in RLS, TDF after HBeAg test is a less costly option.

Prevalence of hepatitis B among childbearing women and infant born to HBV-positive mothers in Togo

Background

Hepatitis B virus (HBV) infection is a public health problem in Togo and transmission to the child occurs mainly during childbirth. The objective of this study was to estimate the prevalence of HBV among childbearing women and infants born to HBV positive mothers in Togo.

Methods

A national cross-sectional study was carried out in six cities in Togo in the six health regions in Togo. Mother-child pairs were recruited from immunization centers or pediatric wards in Lomé, Tsévié, Atakpamé, Sokodé, Kara and Dapaong in 2017. Women aged 18 and over with one child of at least 6 months old were included. A standardized questionnaire was used for data collection and HBV screening was performed using Determine® rapid tests. The prevalence of HBV, defined by a positive HBV surface antigen (HBsAg), was estimated in mothers and then in infants of mothers who were positive for HBsAg. Logistic regression model was performed to identify risk factors for HBsAg positivity in mothers.

Results

A total of 2105 mothers-pairs child were recruited. The median age of mothers and infants was 29 years, interquartile range (IQR) [25–33] and 2.1 years, IQR [1–3] respectively. About 35% of women were screened for HBV during antenatal care and 85% of infants received three doses of HBV immunization. Among mothers, the prevalence of HBV was 10.6, 95% confidence interval (95% CI) [9.4–12.0%], and 177 had detectable HBV viral load (> 10 IU/mL). Among mothers with positive HBsAg, three infants also had positive HBsAg, a prevalence of 1.3, 95% CI [0.2–3.8%]. In multivariable analysis, HIV-infection (aOR = 2.19; p = 0.018), having at least three pregnancies (aOR = 1.46; p = 0.025) and living in Tsévié (aOR = 0.31; p < 0.001) compared to those living in Lomé, were associated to HBV infection in mothers.

Conclusion

In this study, one out of 10 childbearing women were infected with HBV, but less than 2% of infant born to HBV positive mothers under 5 years’ old who received immunization under the Expanded Program on Immunization were infected. Improving antenatal screening and providing targeted interventions in babies could help eliminate HBV in Togo.

Identifying gaps across the cascade of care for the prevention of HBV mother-to-child transmission in Burkina Faso: Findings from the real world

BACKGROUND

Prevention of mother-to-child transmission (PMTCT) is a challenge for controlling the hepatitis B epidemic. In Sub-Saharan countries, pilot interventions including the screening of pregnant women for HBsAg, implementation of anti-HBV therapy and infant immunization within 24 hours of life are initiated and need to be evaluated. This pilot study aimed to describe the cascade of care for hepatitis B PMTCT in a real life situation, and to identify sociodemographic factors associated with adequate management of pregnant women and infants.

METHOD

The study was conducted from October 1st, 2014 to February 28th, 2016 in the antenatal clinics (ANCV) of Baskuy district which comprises nine first-level public health centres. Univariate and multivariate logistic regression analysis were used to identify sociodemographic factors associated with the likelihood of retention in the cohort, HBV DNA testing, birth dose delivery and HBsAg testing of the children at 6 months of age; P ˂ .05 was selected as cut off for significance.

RESULTS

In this prospective cohort study, of 5200 pregnant women consulting for the antenatal visit, 2261 (43.5%) were proposed pre-test counselling and HBsAg screening and 2220 (98.2%) have agreed to screening. Among 1580 (71.2%) women that came back for the post-counselling interview, 75 were positive for HBsAg (4.8%), 73 (97.3% of the women provided HBsAg result) consented to medical consultation with hepatogastroenterologists and 53 (72.6%); performed the HBV DNA testing. Forty-seven out of 60 (78.3%; 65.8-87.9) children born alive were immunized for HBV within 24 hours of life. Retention in care was associated with the level of education of the infant's father, secondary school or higher was associated with a better retention in care of the women (OR: 6.6; P = .03).

CONCLUSION

Our study shows large gaps in HBV PMTCT. Resources for hepatitis B screening, care and prevention including universal access to the vaccine birth dose should be allocated to reduce infection in HBV exposed infants born in Burkina Faso.

Accuracy of HBeAg to identify pregnant women at risk of transmitting hepatitis B virus to their neonates: a systematic review and meta-analysis

BACKGROUND

Prevention of mother-to-child transmission (MTCT) of hepatitis B virus (HBV) involves neonatal immunoprophylaxis, with a birth dose of hepatitis B vaccine and immune globulin, and provision of peripartum antiviral prophylaxis in highly viraemic women. However, access to assays to quantify HBV DNA levels remains inadequate in resource-poor settings. This study was commissioned by WHO and aimed to identify the HBV DNA threshold for MTCT, to assess the sensitivity and specificity of hepatitis B e antigen (HBeAg) testing to identify pregnant women with HBV DNA levels above this threshold, and to predict MTCT of HBV infection on the basis of HBeAg testing.

METHODS

For this systematic review and meta-analysis, we searched the PubMed, EMBASE, Scopus, CENTRAL, CNKI, and Wanfang databases for studies of pregnant women with chronic HBV infection without concurrent antiviral therapy, published between Jan 1, 2000, and April 3, 2019. Studies were eligible for inclusion if MTCT in mother-child pairs could be stratified by different levels of maternal HBV DNA during pregnancy, if maternal HBeAg status could be stratified by HBV DNA level, and if the MTCT status of infants could be stratified by maternal HBeAg status during pregnancy. Studies that selected pregnant women on the basis of HBeAg serostatus or HBV DNA levels were excluded. Aggregate data were extracted from eligible studies by use of a pre-piloted form; study authors were contacted to clarify any uncertainties about potential duplication or if crucial information was missing. To pool sensitivities and specificities of maternal HBeAg to identify highly viraemic women and to predict MTCT events, we used the DerSimonian-Laird bivariate random effects model. This study is registered with PROSPERO, CRD42019138227.

FINDINGS

Of 9007 articles identified, 67 articles (comprising 66 studies) met the inclusion criteria. The risk of MTCT despite infant immunoprophylaxis was negligible (0·04%, 95% CI 0·00-0·25) below a maternal HBV DNA level of 5·30 log₁₀ IU/mL (200 000 IU/mL) and increased above this threshold. The pooled sensitivity of HBeAg testing to identify HBV DNA levels of 5·30 log₁₀ IU/mL or greater in pregnant women was 88·2% (83·9-91·5) and pooled specificity was 92·6% (90·0-94·5). The pooled sensitivity of HBeAg testing in predicting MTCT of HBV infection despite infant immunoprophylaxis was 99·5% (95% CI 91·7-100) and pooled specificity was 62·2% (55·2-68·7).

INTERPRETATION

Maternal HBV DNA of 5·30 log₁₀ IU/mL or greater appears to be the optimal threshold for MTCT of HBV infection despite infant immunoprophylaxis. HBeAg is accurate to identify women with HBV DNA levels above this threshold and has high sensitivity to predict cases of immunoprophylaxis failure. In areas where HBV DNA assays are unavailable, HBeAg can be used as an alternative to assess eligibility for antiviral prophylaxis.

FUNDING

World Health Organization.

Mother-to-child transmission of hepatitis B: What more needs to be done to eliminate it around the world?

Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is a key component of the hepatitis B burden worldwide. Despite its efficacy to prevent HBV transmission, infant vaccination is not enough to control HBV MTCT. Additional efforts are urgently needed to evaluate and scale-up preventive strategies especially in endemic countries, which are most affected. This review highlights the efficacy and barriers of the currently validated measures for the prevention of HBV MTCT and proposes alternatives adapted to resource-limited settings to eventually achieve HBV elimination worldwide.

Selective Hepatitis B Birth-Dose Vaccination in São Tomé and Príncipe: A Program Assessment and Cost-Effectiveness Study

São Tomé and Príncipe (STP) uses a selective hepatitis B birth-dose vaccination (HepB-BD) strategy targeting infants born to mothers who test positive for hepatitis B virus (HBV) surface antigen. We conducted a field assessment and economic analysis of the HepB-BD strategy to provide evidence to guide development of cost-effective policies to prevent perinatal HBV transmission in STP. We interviewed national stakeholders and key informants to understand policies, knowledge, and practices related to HepB-BD, vaccine management, and data recording/reporting. Cost-effectiveness of the existing strategy was compared with an alternate approach of universal HepB-BD to all newborns using a decision analytic model. Incremental cost-effectiveness ratios (ICERs) were calculated in 2015 USD per HBV-associated death and per chronic HBV case prevented, from the STP health-care system perspective. We found that STP lacked national or facility-specific written policies and procedures related to HepB-BD. Timely HepB-BD to eligible newborns was considered a high priority, although timeliness of HepB-BD was not monitored. Compared with the existing selective vaccination strategy, universal HepB-BD would result in a 19% decrease in chronic HBV infections per year at overall cost savings of approximately 44% (savings of USD 5,441 each year). We estimate an ICER of USD 5,012 saved per HBV-associated death averted. The existing selective HepB-BD strategy in STP could be improved through documentation of policies, procedures, and timeliness of HepB-BD. Expansion to universal newborn HepB-BD without maternal screening is feasible and could result in cost savings if actual implementation costs and effectiveness fall within the ranges modeled.

Assessment of the anti-HBs antibody response in Beninese infants following 4 doses of HBV vaccine, including administration at birth, compared to the standard 3 doses regime; a cross-sectional survey

Hepatitis B virus (HBV) infection remains one of the major neglected health issues worldwide. In sub-Saharan Africa (SSA), HBV endemicity is high, with more than 8% of the population being chronic HBV carriers. Recently, WHO recommended that all infants should receive their first dose of the HBV vaccine as soon as possible after birth. Unfortunately, the incorporation of a birth dose of HBV in the expanded programme immunization (EPI) has not occurred in the majority of countries in SSA. From April to September 2017, a cross-sectional survey was conducted in two vaccine units located in southern Benin. We assessed the sustained anti-HBs antibody response in infants induced by a standard scheme of 3 doses of HBV vaccination (6, 10, 14 weeks) in comparison to a scheme of 4 doses with a birth dose included (0, 6, 10, 14 weeks). Blood samples were systematically collected in the first 140 children aged 9 months and their mothers who had consented to participate for the detection of HBs antigen and the quantification of anti-HBs antibodies. The prevalence of HBV infection among infants and mothers was 2.2% and 7.1%, respectively. Infants who received 4 doses of HBV vaccine had a significantly higher level of anti-HBs antibody than those who received 3 doses of vaccine (557.9 UI/L vs. 386.9 UI/L, respectively, P = 0.03). We also showed that the scheme of 4 doses was associated with a significantly higher sustained protective response in comparison to the scheme of 3 doses (aOR 2.49, 95% CI 1.03-6.03, P = 0.04). This result provides further evidence of the importance of administering HBV vaccine at birth, but also highlights the importance for the prevention of vertical transmissions. Additional studies are needed to better establish the cost-effectiveness of such a 4 doses immunization strategy before implementing the HBV vaccination at birth in the EPI.

Cost-effectiveness of birth-dose hepatitis B vaccination among refugee populations in the African region: a series of case studies

Background

Hepatitis B affects 257 million people worldwide. Mother-to-child hepatitis B virus (HBV) transmission is a preventable cause of substantial morbidity and mortality and poses greatest risk for developing chronic HBV infection. The World Health Organization recommends that all countries institute universal hepatitis B birth dose (HepB BD) vaccination during the first 24 h of life, followed by timely completion of routine immunization. The objective of this analysis was to assess the cost-effectiveness of adding HepB BD vaccination among sub-Saharan African refugee populations where the host country’s national immunization policy includes HepB BD.

Methods

We performed a cost-effectiveness analysis of three hepatitis B vaccination strategy scenarios for camp-based refugee populations in the African Region (AFR): routine immunization (RI), RI plus universal HepB BD, and RI plus HepB BD only for newborns of hepatitis B surface antigen-positive mothers identified through rapid diagnostic testing (RDT). We focused analyses on refugee populations living in countries that include HepB BD in national immunization schedules: Djibouti, Algeria and Mauritania. We used a decision tree model to estimate costs of vaccination and testing, and costs of life-years lost due to complications of chronic hepatitis B.

Results

Compared with RI alone, addition of HepB BD among displaced Somali refugees in Djibouti camps would save 9807 life-years/year, with an incremental cost-effectiveness ratio (ICER) of 0.15 USD (US dollars) per life-year saved. The RI plus HepB BD strategy among Western Saharan refugees in Algerian camps and Malian refugees in Mauritania camps would save 27,108 life-years/year with an ICER of 0.11 USD and 18,417 life-years/year with an ICER of 0.16 USD, respectively. The RI plus RDT-directed HepB BD was less cost-effective than RI plus delivery of universal HepB BD vaccination or RI alone.

Conclusions

Based on our model, addition of HepB BD vaccination is very cost-effective among three sub-Saharan refugee populations, using relative life-years saved. This analysis shows the potential benefit of implementing HepB BD vaccination among other camp-based refugee populations as more AFR countries introduce national HepB BD policies.

Elimination of Vertical Transmission of Hepatitis B in Africa: A Review of Available Tools and New Opportunities

PURPOSE

This review article focuses on preventing vertical transmission of hepatitis B virus (HBV) among pregnant women living in sub-Saharan Africa (SSA), where disease is endemic and the estimated maternal HBV seroprevalence is >8%. Available interventions that have been studied in low- and middle-income countries are compared in terms of efficacy and effectiveness in clinical practice. Global disease-elimination targets, barriers to HBV-prevention efforts, and critical research gaps are discussed.

METHODS

A PubMed literature search in February 2018 identified relevant studies of interventions to reduce or prevent the transmission of HBV during pregnancy or in the peripartum period. Studies that focused on interventions that are currently available or could be made available in SSA were included. Trials conducted in SSA and other low-income countries were prioritized, although studies of interventions in middle- and high-income countries were included.

FINDINGS

Among 127 studies and reports included in the review, 60 included data from SSA. The most cost-effective intervention to reduce HBV infection rates in SSA is timely birth-dose vaccination followed by completion of the 3-dose infant-vaccination series. The identification and treatment of pregnant women with elevated HBV viral load to further reduce the risk for vertical transmission in SSA show promise, but efficacy and tolerability trials in Africa are lacking.

IMPLICATIONS

Scale-up of currently available tools is required to reach HBV disease-elimination goals in SSA. Many countries in SSA are in the process of rolling out national birth-dose vaccination campaigns; this roll out provides an opportunity to evaluate and improve processes in order to expand coverage. Early antenatal care, promotion of facility deliveries, and increased awareness of HBV prevention are also key components of prevention success. Future studies in SSA should identity an HBV-prevention package that is effective, well tolerated, and feasible and can be administered in the antenatal clinic and tailored to vertical-transmission risk.

Hepatitis B virus surface antigen and antibody markers in children at a major paediatric hospital after the pentavalent DTP-HBV-Hib vaccination

OBJECTIVES

The knowledge about outcomes of infant vaccination against HBV infections using the DPT-HepB-Hib vaccine in Ghana is limited. This study therefore investigated the levels of immunity to HBV among children who received the DPT-HepB-Hib vaccine and HBsAg carriage in non-responders. Correlates for non-response or poor response were also investigated.

METHODS

Cross-sectional study. A major paediatric hospital in Accra. Four hundred and twenty four children between the ages of 5 to 32 months who had completed the full vaccination schedule for the DPT-HepB-Hib vaccine.

RESULTS

Of the 424 children, 358 (84.4%) developed anti-HBs while 340 (80.2%) developed ≥10 mIU/ml anti-HBs (sero-protection) and 3 had HBsAg. A binary logistic regression analysis showed that younger children were associated with sero-conversion (p=.022) and sero-protection (p=.021). For anti-HBs titres ≥100 mIU/ml age was a weaker but significant contributor (p=.041), as compared to the number of vaccines from different manufacturers the child used (p=.028). The mean age of those who used a single type of vaccine was higher (14.75 ± 6.056 months; n=268) than those who used vaccines from two or more manufacturers (11.96 ± 4.645 months; n=156), p= <.001 (CI: -3.897 - 1.688), an indication that efforts to procure vaccine from same source when it was initially introduced are waning.

CONCLUSIONS

There is still a residual possibility of infection with HBV in spite of infant vaccination. In the light of possible loss of anamnestic response over time, there is the need to consider a birth dose for HBV vaccination for all neonates or booster dose for infants who may not have received the vaccine at birth. Using vaccines from a single manufacturer is recommended.

FUNDING

None declared.

A decision analytic model for prevention of hepatitis B virus infection in Sub-Saharan Africa using birth-dose vaccination

OBJECTIVE

To compare prenatal maternal hepatitis B virus (HBV) screening and infant vaccination strategies to inform policy on HBV prevention in Sub-Saharan Africa.

METHODS

A decision analytic model was created using previously published data to assess the ability of three intervention strategies to prevent HBV infection by age 10 years. Strategy 1 comprised of universal vaccination with a pentavalent vaccine (HBV, diphtheria, tetanus, pertussis, and Haemophilus influenzae) at age 6 weeks. Strategy 2 comprised of universal HBV vaccine at birth plus pentavalent vaccine. Strategy 3 comprised of maternal prenatal HBV screening and targeted HBV vaccine at birth for all exposed infants plus pentavalent vaccine. The reference strategy provided neither maternal screening nor infant vaccination. Rates of HBV infection and costs were compared.

RESULTS

The reference strategy had an HBV infection rate of 2360 per 10 000 children. The HBV infection rate for strategy 1 was 813 per 10 000 children vaccinated (1547 cases prevented). Strategies 2 and 3 prevented an additional 384 cases and 362 cases, respectively. Inclusion of HBV vaccination at birth was the preferred approach at a willingness-to-pay threshold of US$150.

CONCLUSION

Including a birth-dose HBV vaccine in the standard schedule was both cost-effective and prevented additional infections.

[A plea for introduction of hepatitis B vaccination at birth in Côte d'Ivoire]

The Côte d'Ivoire National Immunization Technical Advisory Group 2015 work plan included elaboration of an opinion on inclusion of hepatitis B vaccination at birth in the Expanded Program on Immunization (EPI) in Côte d'Ivoire. A task force was set up to conduct this assessment according to a systematized method. The task force analysed scientific articles on the burden of hepatitis B in Côte d'Ivoire, the burden of mother-child transmission, the impact of hepatitis B vaccination at birth in countries which have adopted this strategy, the efficacy and safety of hepatitis B vaccine in newborns, the cost-effectiveness of hepatitis B vaccination at birth, and the best strategy to introduce hepatitis B vaccination at birth in the EPI. The National Immunization Technical Advisory Group of Côte d'Ivoire finally recommended introduction of a dose of hepatitis B vaccine at birth in the context of the Expanded Program on Immunization with maintenance of three doses of pentavalent vaccine (DPT-HepB-Hib) at 6, 10, and 14 weeks of age.

The status of hepatitis B control in the African region

The World Health Organization (WHO) African Region has approximately 100 million people with chronic hepatitis B virus (HBV) infection. This review describes the status of hepatitis B control in the Region. We present hepatitis B vaccine (HepB) coverage data and from available data in the published literature, the impact of HepB vaccination on hepatitis B surface antigen (HBsAg) prevalence, a marker of chronic infection, among children, HBsAg prevalence in pregnant women, and risk of perinatal transmission. Lastly, we describe challenges with HepB birth dose (HepB-BD) introduction reported in the Region, and propose strategies to increase coverage. In 2015, regional three dose HepB coverage was 76%, and 16(34%) of 47 countries reported ≥ 90% coverage. Overall, 11 countries introduced HepB-BD; only nine provide universal HepB-BD, and of these, five reported ≥ 80% coverage. From non-nationally representative serosurveys among children, HBsAg prevalence was lower among children born after HepB introduction compared to those born before HepB introduction. However, some studies still found HBsAg prevalence to be above 2%. From limited surveys among pregnant women, the median HBsAg prevalence varied by country, ranging from 1.9% (Madagascar) to 16.1% (Niger); hepatitis B e antigen (HBeAg) prevalence among HBsAg-positive women ranged from 3.3% (Zimbabwe) to 28.5% (Nigeria). Studies in three countries indicated that the risk of perinatal HBV transmission was associated with HBeAg expression or high HBV DNA viral load. Major challenges for timely HepB-BD administration were poor knowledge of or lack of national HepB-BD vaccination guidelines, high prevalence of home births, and unreliable vaccine supply. Overall, substantial progress has been made in the region. However, countries need to improve HepB3 coverage and some countries might need to consider introducing the HepB-BD to help achieve the regional hepatitis B control goal of < 2% HBsAg prevalence among children < 5 years old by 2020. To facilitate HepB-BD introduction and improve timely coverage, strategies are needed to reach both facility-based and home births. Strong political commitment, clear policy recommendations and staff training on HepB-BD administration are also required. Furthermore, high quality nationally representative serosurveys among children are needed to inform decision makers about progress towards the regional control goal.

Battlefield against hepatitis B infection and HCC in Africa

Despite effective and safe hepatitis B virus (HBV) vaccine and antiviral therapies, HBV-related hepatocellular carcinoma (HCC) remains a major cause of deaths in young adults in Africa. There are multiple barriers to control the burden of HBV infection and HCC. In comparison to other major infectious diseases, HBV infection and liver diseases have received remarkably little attention from the global health community. There is an urgent need to improve birth dose vaccine coverage and implementing screening and treatment interventions. This requires a dramatic simplification of the management of chronic hepatitis B in Africa, with access to reliable, robust and inexpensive diagnostic tools and strong support from the local governments and the international health community. This review analyses 1) the characteristics of HBV hepatitis and HCC epidemics in Africa and 2) the barriers and potential solutions to control it.

Hepatitis B vaccination timing: results from demographic health surveys in 47 countries

Objective

To examine the impact of hepatitis B vaccination schedules and types of vaccines on hepatitis B vaccination timing.

Methods

We used data for 211 643 children from demographic and health surveys in 47 low- and middle-income countries (median study year 2012). Data were from vaccination cards and maternal interviews. We grouped countries according to the vaccination schedule and type of vaccine used (monovalent or combination). For each country, we calculated hepatitis B vaccination coverage and timely receipt of vaccine doses. We used multivariable logistic regression models to study the effect of vaccination schedules and types on vaccination delay.

Findings

Substantial delays in vaccination were observed even in countries with fairly high coverage of all doses. Median delay was 1.0 week (interquartile range, IQR: 0.3 to 3.6) for the first dose (n = 108 626 children) and 3.7 weeks (IQR: 1.4 to 9.3) for the third dose (n = 101  542). We observed a tendency of lower odds of delays in vaccination schedules starting at 6 and at 9 weeks of age. For the first vaccine dose, we recorded lower odds of delays for combination vaccines than for monovalent vaccines (adjusted odds ratio, aOR: 0.76, 95% confidence interval, CI: 0.71 to 0.81).

Conclusion

Wide variations in hepatitis B vaccination coverage and adherence to vaccination schedules across countries underscore the continued need to strengthen national immunization systems. Timely initiation of the vaccination process might lead to timely receipt of successive doses and improved overall coverage. We suggest incorporating vaccination timing as a performance indicator of vaccination programmes to complement coverage metrics.

A review of strategies to prevent mother-to-infant transmission of hepatitis B virus infection

Hepatitis B virus (HBV) infection causes long-term, life-threatening liver diseases worldwide. HBV is transmitted through either the horizontal or mother-to-infant route, which is the major route of transmission in endemic areas. Administration of hepatitis B immunoglobulin and hepatitis B vaccine to newborns of infected mothers prevents mother-to-infant transmission. Implementation of a universal hepatitis B vaccination program has proven successful in eliminating the infection and related complications. Nevertheless, efforts are still needed to improve global coverage of the hepatitis B vaccine. Infants born to highly viremic mothers are still at risk of infection despite current immunoprophylaxis. An increasing number of reports have shown promising efficacy and safety profiles with the use of nucleoside/nucleotide analogues in highly viremic pregnant women to prevent mother-to-infant transmission.

Systematic review with meta-analysis: the risk of mother-to-child transmission of hepatitis B virus infection in sub-Saharan Africa

BACKGROUND

The risk of mother-to-child transmission of hepatitis B virus (HBV) has been quoted as 70-90% among women positive for hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), and 5-30% among HBsAg-positive HBeAg-negative women. These risks are derived from Asia; little is known about sub-Saharan Africa.

AIM

To determine the risk of mother-to-child transmission in sub-Saharan Africa, according to maternal HBeAg and type of prophylaxis.

METHODS

We searched Medline, Global Health, Embase, African Journals Online and African Index Medicus. We included observational or interventional studies that enrolled infants of HBV-infected women, and that tested for HBsAg or HBV DNA between 3 and 12 months of age.

RESULTS

Fifteen articles from 11 African countries were included. Among HBeAg-positive women, the pooled risk was 38.3% (95% CI: 7.0-74.4%) without prophylaxis, which was significantly lower than the lower bound of 70-90% risk in the literature (P = 0.007). Among HBeAg-negative women, the pooled risk was 4.8% (95% CI: 0.1-13.3%) without prophylaxis, which lays within the lower range of the 5-30% risk in Asia. By extrapolating the pooled transmission risks to the number of births to infectious mothers, an estimated 1% of newborns (n = 367 250) are annually infected with HBV at birth in sub-Saharan Africa.

CONCLUSIONS

Compared to Asia, the risk of mother-to-child transmission is low in sub-Saharan Africa. However, the annual number of infants perinatally infected with HBV is twice the number of incident paediatric HIV infections in sub-Saharan Africa (n = 190 000). This highlights the importance of preventing mother-to-child transmission of HBV in sub-Saharan Africa, which has been long neglected.

Low vaccine coverage among children born to HIV infected women in Niamey, Niger

BACKGROUND

The effect of mother's HIV-status on child vaccination is an important public health issue in countries with high HIV prevalence. We conducted a study in a primary healthcare center located in Niamey, the capital of Niger, which offers free of charge services to HIV positive and/or underprivileged mothers, with the aim of assessing: 1) vaccination coverage for children 0-36 months old, born to HIV-infected mothers, and 2) the impact of maternal HIV status on child vaccination.

METHODS

Mothers of children less than 36 months old attending the center were interviewed, to collect information on vaccines administered to their child, and family's socio-demographic characteristics.

RESULTS

Overall, 502 children were investigated. Children of HIV-seropositive mothers were less likely to receive follow up vaccinations for Diphtheria-Tetanus-Pertussis (DTP) than those of HIV-seronegative mothers, with a prevalence ratio (PR) of 2.03 (95%CI: 1.58-2.61). Children born to HIV-seropositive mothers were less likely to miss vaccination for MMR than those born to HIV negative mothers, with a RR of 0.46 (95%CI: 0.30-0.72).

CONCLUSIONS

Vaccine coverage among children born to HIV infected mothers was rather low. It is important to favor access to vaccination programs in this population.

HBV carriage in children born from HIV-seropositive mothers in Senegal: The need of birth-dose HBV vaccination

Hepatitis B is a major public health problem in Senegal, a country with high prevalence and a transmission occurring mainly during infancy. Only, one 6-8 weeks vaccination campaign was initiated in 2005 and it was part of the expanded program of immunization. The aim of this study was to determine the prevalence of HBsAg in children born from HIV-seropositive mothers by using dried blood specimens. Specimens were collected between July 2007 and November 2012 from children aged 2-48 weeks in Dakar and decentralized sites working on HIV mother-to-child transmission prevention. HBsAg detection was performed using Architect HBsAg Qualitative II kit (Abbott Diagnostics, Ireland) and for all reactive samples confirmation was done using Architect HBsAg Qualitative II Confirmatory kit (Abbott Diagnostics, Ireland). Nine hundred thirty samples were collected throughout the country with 66% out of Dakar, the capital city. The median age was 20 weeks and 88% of children were less than 1 year of age with a sex ratio of 1.27 in favor of boys. HBsAg was detected in 28 cases giving a global prevalence of 3%. According to age, HBsAg prevalences were 5.1% for children less than 6 weeks, 4.1% and 4.6%, respectively, for those aged 12-18 weeks and 18-24 weeks of age. The HIV prevalence was 2.6% with no HIV/HBV co-infection. This study showed a high rate of HBV infection in children under 24 months, highlighting the need to promote birth-dose HBV vaccination as recommended by WHO.

Hepatitis B virus mother-to-child transmission among HIV-infected women receiving lamivudine-containing antiretroviral regimens during pregnancy and breastfeeding

The study included 309 HIV-infected pregnant women receiving a lamivudine-containing antiretroviral regimen from week 25 of gestational age until 6 months postpartum, during breastfeeding. Twenty-seven of them (8.7%) were hepatitis B virus surface antigen (HBsAg) positive; at baseline, hepatitis B virus (HBV) DNA levels >3 log(10) IU/mL (with a median level of 6.2 log(10) IU/mL) were found in 10 women, who at one, three and six months postpartum had median levels of 5.2 log(10) IU/mL, 4.5 log(10) IU/mL and 2.8 log(10) IU/mL, respectively. Twenty-four of the 30 breast milk samples evaluated had undetectable HBV DNA and the other six had values between 15 and 155 IU/mL. Median lamivudine concentrations were 1070 ng/mL in serum and 684 ng/mL in breast milk. Among the 24 HBV-exposed children with available samples, 16 always tested negative, four had a transient infection, one had an undetermined status and three (12.5%) first tested positive at Month 12 or Month 24. Among the children born to the HBV-uninfected mothers of the same cohort, the rate of HBsAg positivity at 12-24 months was 2% (4/196). Our finding of the absence of significative levels of HBV DNA in the breast milk of co-infected mothers supports the present recommendations for breastfeeding in HBV-infected women. Horizontal transmission can be hypothesized for the infections detected in children at 12-24 months. Children born to HBV-positive mothers remained at higher risk of postnatal HBV acquisition compared to those born to HBV-negative women.

Hepatitis B virus infection in children

For two decades, hepatitis B vaccine has been integrated into national routine childhood vaccination programs in almost all countries. The prevalence of HBsAg has decreased in children worldwide. However, there are children who miss the benefit of hepatitis B vaccine in some regions and countries. Long-term follow-up studies have revealed the clinical outcomes of chronic hepatitis B virus infection in children. A small percentage of chronically infected children develop liver cirrhosis and hepatocellular carcinoma. However, it is controversial who should be treated and when antiviral treatment should be initiated in children. Compared with adult studies, the data are insufficient to evaluate the pathogenesis of hepatitis B infection and the efficacy of antiviral treatment in childhood. New antiviral drugs have been approved for children and adults. Also, oral antiviral drugs are administered to pregnant women to reduce the hepatitis B virus mother-to-child transmission rate.

Hepatitis B virus: Where do we stand and what is the next step for eradication?

Hepatitis B (HB) virus (HBV) infection, which causes liver cirrhosis and hepatocellular carcinoma, is endemic worldwide. Hepatitis B vaccines became commercially available in the 1980s. The World Health Organization recommended the integration of the HB vaccine into the national immunisation programs in all countries. HBV prevention strategies are classified into three groups: (1) universal vaccination alone; (2) universal vaccination with screening of pregnant women plus HB immune globulin (HBIG) at birth; and (3) selective vaccination with screening of pregnant women plus HBIG at birth. Most low-income countries have adopted universal vaccine programs without screening of pregnant women. However, HB vaccines are not widely used in low-income countries. The Global Alliance for Vaccine and Immunization was launched in 2000, and by 2012, the global coverage of a three-dose HB vaccine had increased to 79%. The next challenges are to further increase the coverage rate, close the gap between recommendations and routine practices, approach high-risk individuals, screen and treat chronically infected individuals, and prevent breakthrough infections. To eradicate HBV infections, strenuous efforts are required to overcome socioeconomic barriers to the HB vaccine; this task is expected to take several decades to complete.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Efficacy of hepatitis B sero-vaccination in newborns of African HBsAg positive mothers

BACKGROUND

Maternal-infant transmission of hepatitis B virus (HBV) during birth carries a high risk of chronic HBV infection in infants. Appropriate neonatal prophylaxis is effective in preventing perinatal transmission of HBV. The purpose of this study was to evaluate the protective efficacy of anti-HBV sero-vaccination in newborns of HBsAg positive mothers from Mayotte, French island in the Mozambican canal.

PATIENTS AND METHODS

One-hundred newborns of HBsAg positive mothers were identified retrospectively on the basis of hospital medical record and hepatitis B immune globulin (HBIG) prescriptions review from 1994 to 2007. To determine the rate of protective efficacy of neonatal prophylaxis defined by anti HBs antibodies >10 IU/mL with negative HBsAg, anti HBc and HBV DNA testing, HBV serological markers were performed in vaccinated children.

RESULTS

Eighty-three of 100 newborns (83%) were given a complete sero-vaccination. Maternal HBe Ag status at delivery (available in 93%) was positive in 56 (60%) of cases and HBV viral load (available in 57%) was <5 logIU/mL, between 5 and 7 logsIU/mL and >7 logsIU/mL in 23 (40.4%), 12 (21%) and 22 (38.6%), respectively. HBV markers in all children at a median age of 5 years [IQR 2-8] showed that 76% were protected with anti HBs >10 IU/mL, despite incomplete sero-vaccination in 12 infants; 6% of infants had anti-HBs and anti-HBc positivity with undetectable HBV DNA, 1% had isolated anti HBc while 14% were seronegative. Only 3% had evidence of immunoprophylaxis failure: 1 infant was HBsAg carrier and 2 had detectable HBV DNA without HBsAg (occult HBV infection). The only factor associated with sustained protective efficacy was on time serological control performed within one year of life, whereas maternal age, HBeAg status and HBV viral load on delivery were not.

CONCLUSION

The anti-HBV sero-vaccination of newborns of HBsAg-positive mothers is fairly done in Mayotte and allows a high protection of mother-to-child transmission in a mean endemic area with fair safety. Screening of sero-vaccination failures has to be reinforced in order either to revaccinate or to treat infected children.

Implementing a birth dose of hepatitis B vaccine for home deliveries in Africa--too soon?

Despite the recommendation of the World Health Organization (WHO) to provide the first hepatitis B vaccine dose at birth (within 24h), there are epidemiological, economic and logistical reasons why this may not be the best approach for home births in Africa. The WHO policy presupposes that the epidemiology of hepatitis B infection in Africa is similar to the rest of the world and that the organizational, infrastructural and financial support is adequate. While babies born in health facilities may be relatively easy to immunize at birth, health systems and infrastructures in many resource-poor countries in Africa would be severely challenged, if required to reach home deliveries within 24h of birth.

Control of hepatocellular carcinoma through hepatitis B vaccination in areas of high endemicity: perspectives for global liver cancer prevention

There are approximately 360 millions chronic carriers of Hepatitis B virus worldwide. Patterns of HB carriage are variable from one region to the other. Regions with rates of carriage over 8% are commonly considered as "high endemicity" regions. HB carriers have a very significant lifetime risk of developing chronic liver diseases such as cirrhosis and/or liver cancer (hepatocellular carcinoma, HCC). An efficient HB vaccine is available since the early eighties and has been used since for universal infant vaccination in regions of high endemicity. Observations from Taiwan, where universal infant vaccination was introduced from 1984, show a remarkable, long-lasting protection against carriage and reduction of HCC rates in adolescent and young adults born after the initiation of the programme. Two population-based trials have been set up in the mid-eighties to evaluate lifelong protective effects of infant HB vaccine against liver cancer, in The Gambia (West Africa) and in the area of Qidong, China. In other high-endemicity regions of Asia and Africa, universal infants vaccination has consistently showed a long-lasting high protection against chronic carriage and this is expected to lead to a dramatic decrease of chronic liver disease and liver cancer within the next decades. Here we briefly review the lessons of vaccination programmes and trials in high-endemicity regions, based on data gathered during 15-20years of implementation.

Hepatitis B vaccination: The key towards elimination and eradication of hepatitis B

Hepatitis B virus infection is a global health problem. Worldwide, about 360 million people are chronically infected with the virus. They continue to spread the virus to others and are themselves at risk of chronic liver diseases and hepatocellular carcinoma. The infection can now be treated by antivirals or interferons and the transmission route can be interrupted. Nevertheless, the most effective means is to immunize all susceptible individuals, especially young children, with safe and efficacious vaccines. The combined efforts of vaccination, effective treatment and interruption of transmission make elimination of the infection plausible and may eventually lead to eradication of the virus. Because hepatitis B vaccination has a key role in the control of hepatitis B, properties of this vaccine, its effectiveness in pre-exposure and post-exposure settings, duration of protection after vaccination and the need of booster doses are discussed. Mass hepatitis B vaccination in children decreases the carriage of the virus, and the diseases associated with acute and chronic infection, including hepatocellular carcinoma. Challenges that need to be solved to expand mass vaccination, and the strategies towards elimination and eventual eradication of hepatitis B in the world are also discussed.

The rhesus macaque pediatric SIV infection model - a valuable tool in understanding infant HIV-1 pathogenesis and for designing pediatric HIV-1 prevention strategies

Worldwide, the AIDS pandemic continues almost relentlessly. Women are now representing the fastest growing group of newly infected HIV-1 infected patients. The risk of mother-to-child-transmission (MTCT) of HIV-1 increases proportionally as many of these women are of childbearing age. The screening of pregnant women, the early diagnosis of HIV-1 infection, and the administration of antiretroviral therapy (ART) have helped to reduce MTCT significantly. However, this holds true only for developed countries. In many resource-poor countries, access to ART is limited, and breastfeeding, a major route of HIV-1 transmission, is essential to protect the infant from other infectious diseases preponderant in those geographic regions. HIV-1 infected children, in contrast to adult patients, have higher levels of virus replication that decline only slowly, and a subset progresses to AIDS within the first two years. Thus, it is imperative to understand pediatric HIV-1 pathogenesis to design effective prevention strategies and/or a successful pediatric HIV-1 vaccine. The review summarizes how MTCT of HIV-1 in humans can be modeled in the infant macaque model of SIV infection. Importantly, the infant macaque model of SIV infection provides the opportunity to study early virus-host interactions in multiple anatomic compartments. Furthermore, the review underlines the importance of evaluating SIV/HIV immune responses in the context of the normal developmental changes the immune system undergoes in the newborn. Thus, the pediatric SIV infection model provides a unique resource for preclinical studies of novel intervention therapies and vaccine strategies to stop MTCT of HIV-1.