Efficacy and safety of tenofovir disoproxil fumarate in pregnancy for the prevention of vertical transmission of HBV infection

Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate for Preventing Vertical Transmission in Chronic Hepatitis B Mothers: A Systematic Review and Meta-Analysis

OBJECTIVE

International guidelines recommend maternal tenofovir disoproxil fumarate (TDF) therapy accompanied by infant immunoprophylaxis to prevent hepatitis B virus (HBV) mother-to-child transmission (MTCT) in highly viremic mothers. However, pooled analyses for tenofovir alafenamide (TAF) effects and comparisons between the 2 regimens are lacking.

DESIGN

In this meta-analysis, pairs of independent reviewers performed multiple database searches from inception to 31 March 2024 and extracted data from cohort studies and randomized controlled trials (RCTs) in highly viremic mothers. The outcomes of interest were the reduction of MTCT and safety in the TDF-treated, TAF-treated, and control groups.

RESULTS

We included 31 studies with 2588 highly viremic mothers receiving TDF, 280 receiving TAF, and 1600 receiving no treatment. Compared to the control, TDF therapy reduced the MTCT rate in infants aged 6-12 months (risk ratio: 0.10, 95% confidence interval [CI] .07-.16). Pairwise meta-analysis between TAF and TDF revealed similar effects on reducing MTCT (risk ratio: 1.09, 95% confidence interval .16-7.61). Network meta-analysis showed equal efficacy of the 2 regimens in reducing MTCT (risk ratio: 1.09, 95% CI .15-7.65). The surface under the cumulative ranking curve revealed TDF as the best regimen compared with TAF (probability ranking: .77 vs .72), while receiving a placebo during pregnancy had the lowest efficacy (probability ranking 0.01). There were no safety concerns for mothers and infants in all regimens.

CONCLUSIONS

Compared to placebo or no treatment, maternal TDF and TAF prophylaxis are equally effective and without safety concerns in reducing MTCT in highly viremic mothers.

Vertical Transmission of Hepatitis B Virus-An Update

Hepatitis B virus (HBV) infection is a major public health problem in the world. Approximately 296 million people are chronically infected. In endemic areas, vertical transmission is a common route of transmission. There are several strategies for the prevention of HBV vertical transmission, such as antiviral treatment during the third trimester of pregnancy and immunoprophylaxis to newborns that includes the administration of hepatitis B immune globulin (HBIG) and an HBV vaccine. Despite this, immunoprophylaxis failure can occur in up to 30% of infants born to HBeAg-positive mothers and/or with high viral load. Therefore, management and prevention of HBV vertical transmission is of paramount significance. In this article, we provided a review of the epidemiology, mechanisms of pathogenesis and risk factors of vertical transmission, as well as the strategies implemented to prevent the infection.

Tenofovir disoproxil fumarate therapy to prevent hepatitis B virus vertical transmission-A review of maternal and infant outcomes

Hepatitis B virus (HBV) is a global health problem. Vertical transmission of HBV from HBV surface antigen (HBsAg)-positive mothers to their infants is the most common cause of HBV infection worldwide. The use of passive-active immunoprophylaxis is >90% effective in reducing the risk of vertical transmission, but immunoprophylaxis failure can occur in infants born to mothers with high viraemia. Thus, it is recommended that pregnant women with HBV-DNA level >200 000 IU/ml receive nucleos(t)ide analogue (NA) treatment [i.e. tenofovir disoproxil fumarate (TDF), lamivudine or telbivudine] during third trimester to prevent infant immunoprophylaxis failure. TDF is recommended as the first-line therapy based on available data on efficacy, safety and resistance profile. However, maternal immunological reconstitution following parturition can increase immune-mediated flares to viral antigens that is potentially exacerbated following TDF withdrawal. In this article, we review available data on the efficacy and safety of TDF administration to prevent HBV mother-to-child transmission. We also discuss changes in maternal viral markers [i.e. HBV-DNA, HBV e antigen and HBsAg] and alanine aminotransferase during follow-up post-partum in mothers received NA to prevent HBV vertical transmission.

Long-term safety of infants from mothers with chronic hepatitis B treated with tenofovir disoproxil in China

OBJECTIVE

The physical and neuromental development of infants remains uncertain after fetal exposure to tenofovir disoproxil fumarate (TDF) for the prevention of mother-to-child transmission of HBV. We aimed to investigate the safety of TDF therapy during the third trimester of pregnancy.

DESIGN

Infants from a previous randomised controlled trial were recruited for our long-term follow-up (LTFU) study. Mothers with chronic hepatitis B were randomised to receive TDF therapy or no treatment during the third trimester. Infants' physical growth or malformation, bone mineral density (BMD) and neurodevelopment, as assessed using Bayley-III assessment, were examined at 192 weeks of age.

RESULTS

Of 180 eligible infants, 176/180 (98%) were enrolled and 145/176 (82%) completed the LTFU (control group: 75; TDF-treated group: 70). In the TDF-treated group, the mean duration of fetal exposure to TDF was 8.57±0.53 weeks. Congenital malformation rates were similar between the two groups at week 192. The mean body weight of boys in the control and TDF-treated groups was significantly higher (19.84±3.46 kg vs. 18.47±2.34 kg; p=0.03) and within the normal range (18.48±2.35 kg vs. 17.80±2.50 kg; p=0.07), respectively, when compared with the national standard. Other prespecified outcomes (head circumference, height, BMD, and cognitive, motor, social-emotional, and adaptive behaviour measurements) were all comparable between the groups.

CONCLUSION

Infants with fetal exposure to TDF had normal physical growth, BMD and neurodevelopment at week 192. Our findings provide evidence on the long-term safety of infants after fetal exposure to maternal TDF therapy for preventing hepatitis B transmission.

TRIAL REGISTRATION NUMBER

NCT01488526.

Psychological stress; knowledge, attitude and practice and acceptance of antiviral therapy in pregnant women with hepatitis B in Zhejiang, China: a case comparison study

OBJECTIVES

To determine knowledge, attitude and practice (KAP) and antiviral therapy's acceptance during pregnancy of pregnant women with hepatitis B and influencing factors.

DESIGN

Case-comparison study.

SETTING

The study was conducted in Zhejiang province, China, from September 2019 to December 2020.

PARTICIPANTS

Pregnant and postpartum women with chronic hepatitis B.

PRIMARY AND SECONDARY OUTCOME MEASURES

The stress scores, self-assessed health score, KAP, antiviral therapy's acceptance rate during pregnancy and influencing factors were analysed. The Perceived Stress Scale-10 was used to assess stress. Logistic regression was used to analyse influencing factors on antiviral therapy.

RESULTS

The self-assessed health score of pregnant women without liver diseases (82.4±9.3) was significantly higher than that of pregnant women with chronic hepatitis B (75.5±9.5) and postpartum (75.1±14.1). Psychological stress of pregnant women with chronic hepatitis B was significantly high with a 14.9±3.6 score, but there was no significant difference between hepatitis B postpartum and non-liver disease women (12.7±3.5 vs 12.9±3.5, p=0.75). The acceptance rate of pregnant women with hepatitis B for antiviral therapy was 84.2%, while that of postpartum women was even higher. Logistic regression analysis showed that patients with positive hepatitis B e antigen (HBeAg) (OR, 3.35; 95% CI, 1.21 to 9.26) and higher scores on hepatitis B-related knowledge (OR, 3.52, 95% CI, 2.18 to 5.69) were more likely to accept antiviral therapy during pregnancy.

CONCLUSIONS

Pregnant women with hepatitis B in Zhejiang have heavy psychological stress and a high antiviral therapy acceptance rate during pregnancy. Acceptance is related to HBeAg status and level of understanding of hepatitis B during pregnancy. It is necessary to provide education on hepatitis B to reduce psychological stress and increase acceptance of antiviral therapy during pregnancy.

Kinetics of hepatitis B surface antigen in pregnant women with and without tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent mother-to-infant transmission in highly viremic HBV-infected women. Data on hepatitis B surface antigen (HBsAg) levels in pregnant women are lacking. We aimed to investigate prepartum and postpartum HBsAg kinetics and its correlation with HBV DNA in pregnant women. HBV-infected mothers with HBV DNA ≥7.5 log₁₀  IU/ml were tested for HBsAg and HBV DNA from baseline to 6 months postpartum. Of the 186 pregnant women with comparable baseline HBsAg and HBV DNA, 101 received TDF from the third trimester until 1 month postpartum. At delivery, TDF group had mildly lower HBsAg (4.32 ± 0.47 vs. 4.54 ± 0.35 log₁₀  IU/ml, p = .0004) and markedly lower HBV DNA (4.26 ± 0.97 vs. 8.11 ± 0.70 log₁₀  IU/ml, p < .0001) than the control group. In the TDF group, mean reduction of HBsAg and HBV DNA from baseline to delivery were 0.22 ± 0.38 and 3.96 ± 0.93 log₁₀  IU/ml. HBsAg reduction had a positive correlation (r = .309; p = .0017) with HBV DNA reduction, and was predictive of HBV DNA reduction ≥3 log₁₀  IU/ml (area under the receiver operating characteristic curve, 0.67; 95% confidence interval, 0.50-0.82). At 6 months postpartum, TDF and control group had comparable HBsAg and HBV DNA. In conclusion, HBsAg decreased slightly at delivery in pregnant women receiving TDF. For monitoring the effect of antiviral therapy during pregnancy, HBV DNA is a better marker than HBsAg. Our data provided valuable information regarding monitoring HBV-infected pregnant women using antiviral therapy.

Proximal tubular dysfunction in pregnant women receiving tenofovir disoproxil fumarate to prevent mother-to-child transmission of hepatitis B virus

BACKGROUND

Data evaluating the risk of proximal tubular dysfunction in women receiving tenofovir disoproxil fumarate for the prevention of mother-to-child transmission (PMTCT) of HBV are scarce.

OBJECTIVES

To assess the risk of proximal tubulopathy in pregnant women receiving tenofovir disoproxil fumarate for PMTCT of HBV.

PATIENTS AND METHODS

We used urine samples collected from HBV monoinfected pregnant women who participated in a Phase III, multicentre, randomized, double-blind, placebo-controlled clinical trial assessing a tenofovir disoproxil fumarate short course from 28 weeks gestational age (28-wk-GA) to 2 months post-partum (2-months-PP) for PMTCT of HBV in Thailand. Markers of tubular dysfunction, including retinol binding protein, kidney injury molecule-1, α1-microglobuin and β2-microglobulin, were assayed at 28- and 32-wk-GA and 2-months-PP visits. Proximal tubulopathy was defined as the presence of ≥2 of the following: tubular proteinuria, euglycaemic glycosuria and increased urinary phosphate.

RESULTS

A total of 291 women participated in the study. No kidney-related adverse events were severe, and none led to tenofovir disoproxil fumarate discontinuation. At 2-months-PP, 3 of the 120 (3%) evaluated women in the tenofovir disoproxil fumarate group experienced proximal tubulopathy versus 3 of 125 (2%) in the placebo group (P  = 1.00). None of the six women met the criteria for proximal tubulopathy at 12-months-PP but proteinuria persisted in three of them. No growth abnormalities were found at 1 year of age in infants born to mothers with proximal tubulopathy at 2-months-PP.

CONCLUSIONS

In these HBV-infected pregnant and breastfeeding women, tenofovir disoproxil fumarate administered from 28-wk-GA to 2-months-PP was not associated with a higher risk of proximal tubulopathy.

Hepatitis B: Who should be treated?-managing patients with chronic hepatitis B during the immune-tolerant and immunoactive phases

New hepatitis B virus (HBV) infections are decreasing owing to improved antiviral therapy and increased HBV vaccination worldwide; however, the number of HBV infections remains a major cause of liver carcinogenesis. HBV triggers cytotoxic immunity to eliminate HBV-infected cells. Therefore, the HBV pathophysiology changes in persistently infected individuals depending on host immune responses and HBV DNA proliferation state. To prevent liver cirrhosis and carcinogenesis caused by HBV, it is important to treat HBV infection at an early stage. Active treatment is recommended for the immunoactive hepatitis B surface-antigen-positive and -negative phase, but not during the immune-inactive phase or immune-tolerant phase; instead, follow-up is recommended. However, these patients should be monitored through regular blood tests to accurately diagnose the immune-inactive or -tolerant phases. The treatment regimen should be determined based on the age, sex, family history of liver cancer, and liver fibrosis status of patients. Early treatment is often recommended due to various problems during the immune-tolerant phase. This review compares the four major international practice guidelines, including those from the Japanese Society of Hepatology, and discusses strategies for chronic hepatitis B treatment during the immune-tolerant, immune-inactive, and resolved phases. Finally, recommended hepatitis B antiviral therapy and follow-up protocols are discussed.

Prevention of hepatitis B mother-to-child transmission in Namibia: A cost-effectiveness analysis

Despite access to a safe and effective vaccine, mother-to-child transmission (MTCT) of hepatitis B virus (HBV) persists in Africa. This is of concern since perinatally-infected infants are at highest risk of developing hepatocellular carcinoma, a life-threatening consequence of chronic HBV infection. While tools to prevent HBV MTCT are available, the cost implications of these interventions need consideration prior to implementation. A Markov model was developed to determine the costs and health outcomes of (1) universal HBV birth dose (BD) vaccination, (2) universal BD vaccination and targeted hepatitis B immunoglobulin (HBIG), (3) maternal antiviral prophylaxis using sequential HBV viral load testing added to HBV BD vaccination and HBIG, and (4) maternal antiviral prophylaxis using sequential HBeAg testing combined with HBV BD vaccination and HBIG. Health outcomes were assessed as the number of paediatric infections averted and disability-adjusted life years (DALYs) averted. Primary cost data included consumables, human resources, and hospital facilities. HBV epidemiology, transitions probabilities, disability weights, and the risks of HBV MTCT were extracted from the literature. Incremental cost-effectiveness ratios (ICERs) were calculated to compare successive more expensive interventions to the previous less expensive one. One-way sensitivity analyses were conducted to test the robustness of the model's outputs. At the Namibian cost/DALY averted threshold of US$3 142, the (1) BD vaccination + targeted HBIG, and (2) maternal antiviral prophylaxis with sequential HBeAg testing interventions were cost-effective. These interventions had ICERs equal to US$1909.03/DALY and US$2598.90/DALY averted, respectively. In terms of effectiveness, the maternal antiviral prophylaxis with sequential HBeAg testing intervention was the intervention of choice. The analysis showed that elimination of HBV MTCT is achievable using maternal antiviral prophylaxis with active and passive immunization. There is an urgent need for low cost diagnostic tests to identify those women who will most benefit from drug therapy to attain this laudable goal.

Pharmacokinetics of oral tenofovir disoproxil fumarate in pregnancy and lactation: a systematic review

BACKGROUND

Tenofovir disoproxil fumarate (TDF), the oral prodrug of tenofovir (TFV), is advocated in pregnancy for prevention of mother-to-child transmission (PMCT) with failure of hepatitis B immunoglobulin and vaccination. The pharmacokinetics of TDF monotherapy for PMCT-HBV is important if deployment is to emulate the success of multiple antiretrovirals (ARVs) for PMCT-HIV in resource-constrained settings.

METHODS

This systematic review followed a protocol and is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) guidelines. We included studies that enrolled pregnant women who received oral TDF therapy as monotherapy or in combination with other ARVs: irrespective of the reason for receiving the drug (for example, HIV, HBV or pre-exposure prophylaxis); and reported pharmacokinetics.

RESULTS

The area under the concentration-time curve (AUC), maximum plasma concentrations (C_max) and last measurable plasma concentration (C_last) of TFV were decreased in the second and third trimester compared with first trimester or post-partum. In none of the manuscripts was the non-pregnant HBV threshold of C_max of 300 ng/ml reached, but the 50% effective concentration (EC₅₀) of TFV is lower for treatment of HBV compared with HIV. The TFV concentration in breastfed infants was 0.03% of the recommended infant dose.

CONCLUSIONS

Most knowledge of pharmacokinetics of TFV in pregnancy results from studies on HIV involving multiple ARVs. Increased TFV clearance occurred in the second and third trimester when optimal TFV concentrations are required to maximize suppression of HBV in the window before birth. Dose or duration adjustments will be better conceptualized with concurrent analysis of the pharmacokinetics of TFV monotherapy and hepatitis B pharmacodynamics in pregnancy.

Efficacy and Safety of Tenofovir in the Prevention of Perinatal Transmission of Hepatitis B, a Meta-Analysis

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is recommended for the prevention of perinatal transmission of the hepatitis B virus (HBV). This study aimed to systematically assess the efficacy and safety of TDF in pregnant women with chronic HBV and their infants.

MATERIAL AND METHODS

Database searches were performed to identify studies blocking the mother-to-child transmission of the hepatitis B virus with tenofovir. The search included pregnant women with chronic HBV infection administered with TDF compared to the no treatment controls, and data from individual studies were pooled using RevMan v5.3 for meta-analysis.

RESULTS

Seven studies with a total of 911 patients met the inclusion criteria: 433 patients in the TDF group and 478 patients in the non-TDF group. The HBV mother-to-child transmission rate in the tenofovir group was effectively reduced compared to the control group (RR: 0.18, 95% CI: 0.08-0.40). HBV-DNA positivity was also significantly low in infants from TDF group (RR: 0.17, 95% CI: 0.10-0.30) and the TDF treatment resulted in significantly higher anti-HBs production (RR: 1.11, 95% CI: 1.04-1.18). Similarly, maternal HBV-DNA was suppression was significantly high in the TDF group (RR: 34.16, 95% CI: 16.40-71.13). Women treated with TDF and their infants did not result in serious adverse events that are statistically different as compared to the women who did not receive any treatment.

CONCLUSION

Treatment of HBV infected pregnant women with TDF can effectively and safely prevent the perinatal transmission of chronic hepatitis B.

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

BACKGROUND

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

METHODS

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

MAIN BODY

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

CONCLUSION

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

Efficacy and safety of antiviral prophylaxis during pregnancy to prevent mother-to-child transmission of hepatitis B virus: a systematic review and meta-analysis

BACKGROUND

To eliminate mother-to-child transmission (MTCT) of hepatitis B virus (HBV), peripartum antiviral prophylaxis might be required for pregnant women infected with HBV who have a high risk of MTCT despite infant immunoprophylaxis. We aimed to determine the efficacy and safety of peripartum antiviral prophylaxis to inform the 2020 WHO guidelines.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, Scopus, CENTRAL, CNKI, and Wanfang for randomised controlled trials and non-randomised studies of peripartum antiviral prophylaxis versus placebo or no prophylaxis, with no language restriction, published from database inception until March 28, 2019. We used search terms covering HBV, antiviral therapy, and pregnancy. We included studies that enrolled pregnant women with chronic infection with HBV who received antiviral prophylaxis anytime during pregnancy; that included any of the following antivirals: adefovir, emtricitabine, entecavir, lamivudine, telbivudine, tenofovir alafenamide fumarate, and tenofovir disoproxil fumarate; and that reported the following outcomes: MTCT, indicated by infant HBsAg positivity or HBV DNA positivity, or both, at age 6-12 months, and any infant or maternal adverse events. Two reviewers independently extracted data. Our primary endpoint was MTCT based on infant HBsAg positivity. We assessed pooled odds ratios (ORs) of the efficacy of peripartum antiviral prophylaxis to reduce the risk of MTCT. We assessed safety of prophylaxis by pooling risk differences. The protocol for the systematic review was pre-registered in PROSPERO, CRD42019134614.

FINDINGS

Of 7463 articles identified, 595 articles were eligible for full-text review and 129 studies (in 157 articles) were included. The following antivirals were assessed in the meta-analysis: tenofovir disoproxil fumarate 300 mg (19 studies, with 1092 mothers and 1072 infants), lamivudine 100-150 mg (40 studies, with 2080 mothers and 2007 infants), and telbivudine 600 mg (83 studies, with 6036 mothers and 5971 infants). The pooled ORs for randomised controlled trials were similar, at 0·10 (95% CI 0·03-0·35) for tenofovir disoproxil fumarate, 0·16 (0·10-0·26) for lamivudine, and 0·14 (0·09-0·21) for telbivudine. The pooled ORs in non-randomised studies were 0·17 (0·10-0·29) for tenofovir disoproxil fumarate, 0·17 (0·12-0·24) for lamivudine, and 0·09 (0·06-0·12) for telbivudine. We found no increased risk of any infant or maternal safety outcomes after peripartum antiviral prophylaxis.

INTERPRETATION

Peripartum antiviral prophylaxis is highly effective at reducing the risk of HBV MTCT. Our findings support the 2020 WHO recommendation of administering antivirals during pregnancy, specifically tenofovir disoproxil fumarate, for the prevention of HBV MTCT.

FUNDING

World Health Organization.

Prevention strategies of mother-to-child transmission of hepatitis B virus (HBV) infection

Chronic hepatitis B virus (HBV) infection caused by mother-to-child transmission (MTCT, also known as vertical transmission) during the perinatal period is a major public health problem worldwide. Despite the availability of the combined active-passive immunization with a hepatitis B vaccine and hepatitis B immunoglobulin after birth, about 9% of newborns are still infected with HBV, especially those born to hepatitis B e antigen (HBeAg)-positive mothers. Currently, the management of HBV infection during pregnancy remains controversial. This article briefly reviews the recent advances in the epidemiology of HBV, immunization against it, and management strategies in the third trimester.

Efficacy and safety of antiviral therapy for HBV in different trimesters of pregnancy: systematic review and network meta-analysis

BACKGROUND

Several antiviral agents licenced for blocking mother-to-child transmission (MTCT) of HBV, but their relative efficacy beginning from different trimesters has scarce been evaluated. We aimed to conduct a network meta-analysis to statistically differ the efficacy and safety of each antiviral agents initiating on different timings in preventing mother-to-infant transmission of HBV.

METHODS

Studies were included from PubMed, EMBASE, Web of Science, and Cochrane databases through July 1, 2019. Eligible studies recruited randomized controlled trials and nonrandomized studies reporting about infant or/and maternal efficacy and safety outcomes and were screened by two investigators independently. Extracted data were analyzed by pair-wised and network meta-analysis, respectively.

RESULTS

3 Randomized and 32 nonrandomized studies enrolling 6738 pregnant female were included. Using network analysis, any antiviral agent interrupted HBV vertical transmission much more effectively than placebo. No agent showed significant efficacy different from others, but a strong trend toward significance was found in telbivudine and tenofovir, of which had the highest probability of being ranked the first- or second-best treatment for reducing MTCT of HBV. The treatment applied in the first and second trimester had a similar efficacy in preventing MTCT. Compared with the initiation during the third trimester, lower rate of MTCT was revealed when antiviral therapy was administrated before third trimester, (RR = 0.045, 95% CI 0.0053 to 0.20); a similar effect at delivery on suppressing maternal HBV DNA level and converting serum HBeAg were achieved if the timing of antiviral treatment started prior, but an obvious improvement of normalizing ALT flare was calculated out; no statistically differences among maternal and fetal safety outcomes were found if mothers received antiviral agents before pregnant 28 weeks.

CONCLUSION

This network meta-analysis recommended the earlier use of telbivudine or tenofovir, tends to be better to prevent MTCT of HBV in pregnancy with no increased adverse maternal or fetal outcomes.

Clinical efficacy and safety in telbivudine- or tenofovir-treated hepatitis B e antigen-positive pregnant women

BACKGROUND

Telbivudine (LdT) and tenofovir (TDF) are widely used in pregnant women to prevent vertical transmission; however, limited data are available on the differences in clinical efficacy and safety between the two drugs.

METHODS

A total of 307 hepatitis B e antigen (HBeAg)-positive pregnant women with complete follow-up data were enrolled, the patients with alanine aminotransferase (ALT) levels <1×ULN at baseline were enrolled to cohort 1 for treatment from 28 ±4 weeks gestation to delivery, while ALT levels >1×ULN at baseline were enrolled to cohort 2 for treatment from 28 ±4 weeks gestation and continued after delivery. The clinical efficacy and safety was compared in LdT- and TDF-treated patients. In addition, 32 patients in cohort 1 were analysed for nucleoside analogue (NA)-related resistance mutations at baseline and after delivery.

RESULTS

The results showed that HBV DNA levels were significantly lower at delivery than at baseline (P<0.001), but the decreases in HBV DNA, ALT, total bilirubin and total bile acid levels did not differ between the LdT- and TDF-treated patients at different time points (P>0.05) in the two cohorts. However, gastrointestinal adverse effects (vomiting) occurred more frequently in TDF-treated than LdT-treated patients (6.6% versus 0.0%; P=0.001). The results of NA-related resistance mutations analysis in cohort 1 revealed that short-term LdT or TDF treatment did not significantly change the NA-related resistance mutations (P>0.05).

CONCLUSIONS

This study revealed that the clinical efficacy in LdT- or TDF-treated HBeAg-positive Chinese pregnant women is similar, and gastrointestinal adverse effects occurred more frequently in TDF-treated patients.

Efficacy and safety of telbivudine and tenofovir disoproxil fumarate in preventing hepatitis B vertical transmission: A real-life practice

Mother-to-child transmission (MTCT) is a major obstacle in the elimination of hepatitis B virus (HBV) infection. Telbivudine (LdT) and tenofovir disoproxil fumarate (TDF) are the two most common antiviral medicines for preventing MTCT. However, the efficacy and safety of LdT and TDF in preventing HBV vertical transmission during the second to third trimester have not been compared rigorously. Therefore, we carried out a prospective multicentre cohort study of chronic hepatitis B in mothers with HBV DNA > 10⁶  IU/mL, receiving LdT or TDF during the second to third trimester. Among the 893 mothers enrolled, 857 (LdT/TDF/untreated group (NTx) = 396/325/136) completed consecutive follow-up with 854 infants (LdT/TDF/NTx = 395/323/136). LdT and TDF treatment resulted in a similar decrease of HBV DNA in mothers at delivery. Multivariate analysis indicated that only HBsAg titre at the baseline correlated with viral DNA decrease (P = 0.015). With intention-to-treat analysis, MTCT rates in the LdT, TDF and NTx group were 4.41%, 2.42% and 22.08%, respectively. An increasing vertical transmission rate was found to be closely associated with higher HBsAg titre, 5.32% and 17.65% infection rate was estimated in infants born to mothers with HBsAg > 4 and >5 log₁₀ IU/mL, respectively. No serious side effects were reported in either mothers or infants. LdT and TDF treatments were well tolerated and showed comparable efficacy in reducing MTCT. Higher risk of MTCT was shown in pregnant women with HBsAg > 4 log₁₀ IU/mL.

Comparing the Efficacy and Safety of Treating Chronic Hepatitis B Infection during Pregnancy with Lamivudine, Telbivudine, and Tenofovir: A Meta-analysis

Background and Aims: The perinatal transmission of hepatitis B virus (HBV) remains an important global health problem. Here, a systematic review and meta-analysis were conducted to evaluate the evidence regarding the efficacy and maternal/fetal safety of treating pregnant women with lamivudine, telbivudine (LdT), and tenofovir (TDF). Methods: A PubMed and Scopus search resulted in 1,076 records, which were reduced to 36, containing 7,717 pregnant women with chronic HBV infection and 7467 infants meeting the inclusion criteria. The latest search was in August 2019. Results: Treatment with LdT, but not lamivudine and TDF, could significantly reduce the hepatitis B virus surface antigen-positive rate (odds ratio (OR) = 0.37) in infants; it also led to higher rates of hepatitis B e antigen loss (OR = 12.14), hepatitis B e antigen seroconversion (OR = 8.93), and alanine aminotransferase normalization in mothers (OR = 1.49). Each of these treatments was able to significantly reduce HBV DNA positivity at birth (total OR = 0.19) and mother-to-child-transmission of HBV (total OR = 0.15), and to cause higher rates of HBV DNA suppression in mothers (total OR = 25.53). However, nucleos(t)ide analogues might also be involved in creatine kinase elevation (total OR = 7.48). In contrast, no significant association was found between nucleos(t)ide analogue therapy and preterm/premature births, congenital malformation, low birth weight, and abortion or fetal/infant death. The results suggested LdT's high capability of preventing mother-to-child-transmission. However, TDF failed to show significant associations to a reduced risk of mother-to-child-transmission, probably due to the low number of patients included. Conclusions: Although using either lamivudine, LdT, or TDF could lead to more favorable maternal/fetal outcomes, LdT seemed to show more potential in resolving certain infant- and maternal-related outcomes. More studies on the safety profile of such treatments are required.

Hepatitis B virus sero-prevalence amongst pregnant women in the Gambia

BACKGROUND

Infection with Hepatitis B virus (HBV) is a serious public health problem worldwide, with over 360 million carriers. Sixty million of these are resident in Sub-saharan Africa. Hepatitis B infection is the cause of Hepatocellular carcinoma (HCC), which is the second commonest cause of death from cancers among women in The Gambia. Vertical transmission is the commonest route of spread of Hepatitis B Virus in many endemic areas. The main aim of the study was to determine the sero-prevalence of Hepatitis B surface antigen (HBsAg) among pregnant women attending antenatal clinic at the Edward Francis Small Teaching Hospital, Banjul, The Gambia.

METHODS

Four hundred and twenty six pregnant women were recruited from our antenatal clinics and tested for HBsAg. Serum Hepatitis B surface antigen (HBsAg) was tested using commercial rapid diagnostic Elisa kits at the point of care.

RESULTS

A prevalence rate of 9.20% among all pregnant women studied was found. Women who were likely to have been vaccinated had a prevalence rate of 2.30% whiles those unlikely to have been vaccinated had a prevalence of 13.71%. There was a statistically significant difference between those likely to have been vaccinated and those unlikely to have been vaccinated.

CONCLUSION

The prevalence of hepatitis B infection is very high among pregnant women at EFSTH as in the high endemic zone that is more than 8%. However the prevalence rate is lower than the national average of 15%. The prevalence is of moderate endemicity among the women who likely received vaccination during childhood. More interventions during pregnancy need to be undertaken if more successes are to be registered.

Novel insights in the prevention of perinatal transmission of hepatitis B

Perinatal transmission of hepatitis B virus (HBV) infection is major contributor to the growing burden of chronic hepatitis B worldwide. Administration of HBV immunoglobulin and HBV vaccination as soon after pregnancy as possible are the mainstay of prevention of perinatal transmission of HBV infection. In women with high viral loads, antiviral prophylaxis also appears to be useful. Lamivudine, telbivudine and tenofovir have been shown to be both safe and effective in this setting but tenofovir is the first-line option due to its low potential for resistance and more favorable safety profile.

Efficacy of tenofovir in preventing perinatal transmission of HBV infection in pregnant women with high viral loads

Mother-to-child transmission is the major cause of chronic hepatitis B virus (HBV) infection. This double-blind trial tested the effect of tenofovir disoproxil fumarate (TDF) in preventing vertical transmission. Pregnant women who were HBsAg/HBeAg-positive with a HBV DNA titer ≥ 2×106 IU/mL were randomly assigned to the control (n = 60) and TDF-treated (n = 60) groups. TDF treatment (oral dose 300 mg/day) was initiated at 24 weeks of gestation and continued to 4 weeks after delivery. The subjects were followed up to 28 weeks postpartum. The effects of TDF on vertical transmission, outcomes of the mothers and infants and virological changes were monitored. TDF dynamically reduced the serum HBV DNA level of the mothers, particularly during the first 4 weeks of treatment. The lower viral loads were maintained in the pregnancies until delivery. Approximately 90% and 33.9% of the TDF-treated mothers had viral loads ≤2000 IU/mL after delivery and at 28 weeks postpartum, respectively. No cervical transmission or adverse effects were observed in the TDF-treated individuals, whereas 13.5% of the infants were infected with HBV in the control group. We conclude that TDF treatment initiated at 24 weeks of gestation in high-viremia, HBsAg/HBeAg-positive mothers efficiently prevents mother-to-child HBV transmission without adverse events in mothers and infants.

Synthetic therapeutics for the treatment of hepatitis B during pregnancy

INTRODUCTION

Hepatitis B infection in pregnancy mandates careful monitoring and specialized management according to the phase of hepatitis B infection. Perinatal transmission may be prevented by antiviral therapy in mothers with high viral load and timely immunoprophylaxis of the infant.

AREAS COVERED

This review focuses on the current first-line therapies for treating hepatitis B in pregnancy, timing of therapy, and prevention of perinatal transmission. Strategies to manage disease at the various phases and potential emerging therapies in phase III of development are also covered. Medline/PubMed and Cochrane databases were searched systematically from 1990 to April 2018 with the relevant articles selected for the review.

EXPERT OPINION

Universal antenatal screening for hepatitis B and strict immunoprophylaxis for infants form the cornerstones to prevent hepatitis B virus (HBV) perinatal transmission. Tenofovir is the preferred drug for treatment in pregnancy in view of its good efficacy and high barrier to resistance. Most of the data on antivirals are from cohort studies which are prone to bias and more randomized controlled trials (RCTs) are needed to establish the benefits and safety of these drugs in pregnancy. Various novel drugs are in the pipeline which may pave the way for a cure in the near future.

Efficacy and safety of tenofovir in preventing mother-to-infant transmission of hepatitis B virus: a meta-analysis based on 6 studies from China and 3 studies from other countries

BACKGROUND

The vertical transmission of HBV from mothers to their infants at birth or in early infancy has a significant role in the endemicity of HBV infection. Tenofovir is one of the most potent anti-HBV agents with a high genetic barrier to resistance. The study is to evaluate the efficacy of tenofovir in preventing perinatal HBV transmission, as well as monitoring safety for mothers and infants.

METHODS

PubMed, Embase, Web of Science, and CNKI (National Knowledge Infrastructure, China) database were systematically reviewed for studies that compared the efficacy and safety of tenofovir with other treatments. Pooled estimates were expressed with weight mean difference (WMD) with 95% confidence intervals (95% CIs) and risk ratio (RR) with 95% CIs.

RESULTS

Nine studies involving 1046 pregnant patients met the inclusion criteria and were included in this meta-analysis. Compared with other treatments, tenofovir significantly reduced maternal HBV DNA levels (WMD = 2.33 log10 IU/mL, 95% CI: 1.01, 3.64; P < 0.001), infant HBsAg positivity rate (RR = 0.25, 95% CI: 0.16, 0.38; P < 0.001), infant HBeAg positivity rate (RR = 0.26, 95% CI: 0.14, 0.48; P < 0.001), infant HBV DNA positivity rate (RR = 0.15, 95% CI: 0.07, 0.31; P < 0.001), and immunoprophylaxis failure rate (RR = 0.31, 95% CI: 0.13, 0.73; P = 0.008). Moreover, maternal and infant safety profiles, including ALT, CK, and Cr were comparable between tenofovir and other treatment groups.

CONCLUSION

Based on the current evidence, our study suggested that tenofovir significantly reduced the rate of vertical transmission of HBV, as well as the HBV DNA levels in HBV-infected mothers. Moreover, tenofovir was safe and tolerable for both mothers and their infants.

Birth Outcomes for Pregnant Women with HIV Using Tenofovir-Emtricitabine

BACKGROUND

In a previous trial of antiretroviral therapy (ART) involving pregnant women with human immunodeficiency virus (HIV) infection, those randomly assigned to receive tenofovir, emtricitabine, and ritonavir-boosted lopinavir (TDF-FTC-LPV/r) had infants at greater risk for very premature birth and death within 14 days after delivery than those assigned to receive zidovudine, lamivudine, and ritonavir-boosted lopinavir (ZDV-3TC-LPV/r).

METHODS

Using data from two U.S.-based cohort studies, we compared the risk of adverse birth outcomes among infants with in utero exposure to ZDV-3TC-LPV/r, TDF-FTC-LPV/r, or TDF-FTC with ritonavir-boosted atazanavir (ATV/r). We evaluated the risk of preterm birth (<37 completed weeks of gestation), very preterm birth (<34 completed weeks), low birth weight (<2500 g), and very low birth weight (<1500 g). Risk ratios with 95% confidence intervals were estimated with the use of modified Poisson models to adjust for confounding.

RESULTS

There were 4646 birth outcomes. Few infants or fetuses were exposed to TDF-FTC-LPV/r (128 [2.8%]) as the initial ART regimen during gestation, in contrast with TDF-FTC-ATV/r (539 [11.6%]) and ZDV-3TC-LPV/r (954 [20.5%]). As compared with women receiving ZDV-3TC-LPV/r, women receiving TDF-FTC-LPV/r had a similar risk of preterm birth (risk ratio, 0.90; 95% confidence interval [CI], 0.60 to 1.33) and low birth weight (risk ratio, 1.13; 95% CI, 0.78 to 1.64). As compared to women receiving TDF-FTC-ATV/r, women receiving TDF-FTC-LPV/r had a similar or slightly higher risk of preterm birth (risk ratio, 1.14; 95% CI, 0.75 to 1.72) and low birth weight (risk ratio, 1.45; 95% CI, 0.96 to 2.17). There were no significant differences between regimens in the risk of very preterm birth or very low birth weight.

CONCLUSIONS

The risk of adverse birth outcomes was not higher with TDF-FTC-LPV/r than with ZDV-3TC-LPV/r or TDF-FTC-ATV/r among HIV-infected women and their infants in the United States, although power was limited for some comparisons. (Funded by the National Institutes of Health and others.).

Update on the management of hepatitis B and C infections in the neonatal period

Hepatitis B virus and hepatitis C virus have received a significant amount of attention in recent years, and both viruses share a significant amount of similarities with one another beyond just that they both primarily target the liver. In recent years, cases of both infections have been fueled by a nationwide epidemic of injection drug use. Most relevant to this audience, they are both transmitted from mother to child. The increased cases in young adults combined with mother to child transmission translate into more exposed infants that will need to be managed and followed. Screening of pregnant women for hepatitis B infection coupled with appropriate treatment and prophylaxis measures are incredibly effective to preventing transmission. Prevention of hepatitis C infection is not yet possible, but advances in antiviral therapy make interruption of transmission a future possibility.

Nucleoside/nucleotide analogues in the treatment of chronic hepatitis B infection during pregnancy: a systematic review

BACKGROUND

Women of childbearing age who have developed chronic hepatitis B (CHB) infection, especially HBeAg-positive highly viraemic pregnant women, are largely responsible for the familial transmission of the infection. Therefore, choosing the most effective and safest antiviral medications to manage pregnant CHB patients is of crucial importance.

MATERIALS AND METHODS

The PubMed and Scopus databases were searched through September 2017, for all the journal articles possessing original results regarding treatment of CHB pregnant women with any nucleos(t)ide analogue (NA) therapies, including lamivudine (LAM), adefovir (ADV), entecavir (ETV), telbivudine (LdT), and tenofovir (TDF).

RESULTS

After the primary search, 882 studies were recognized, and updating the searching results, 41 journal articles with original data were investigated, involving 3874 newborn infants from mothers with CHB, and their mothers completed follow-up until the delivery. The most important basic data and results regarding the efficacy of drugs, the rate of vertical transmission, safety issues associated with pairs of mothers and infants, median levels of HBV DNA, breastfeeding data, and rate of rate of vaccination success were collected. Moreover, possible key conclusion, recommendations, and learned lessons were discussed. Among the evaluated NAs, all LAM was efficient and safe. LdT was found to be very effective but had some safety concerns. In contrast, TDF had the advantages of both effectiveness and safety.

CONCLUSION

According to data in the literature, initiation of TDF at the trimester of pregnancy in combination with immunoprophylaxis to prevent mother-to-child transmission (MTCT) of CHB infection is strongly recommended as well as successful immunization of CHB pregnant women by anti-HBV vaccines.

PrEP as Peri-conception HIV Prevention for Women and Men

Daily oral tenofovir (TDF)-based pre-exposure prophylaxis (PrEP) is an effective HIV prevention strategy and recommended for men and women with substantial risk of HIV acquisition. The peri-conception period, the stage prior to pregnancy when condom use is necessarily reduced, has elevated HIV risk that can be mitigated by PrEP use. Data from a randomized trial suggest that peri-conception PrEP use by HIV-seronegative women does not increase the risk of pregnancy loss, birth defects or congenital anomalies, preterm birth, or infant growth faltering. Women considering PrEP use throughout pregnancy must weigh the known increased risk of HIV acquisition with unknown risks of drug effects on infant growth. PrEP has been used safely by HIV-seronegative men with HIV-seropositive female partners who have become pregnant. As an effective user-controlled HIV prevention strategy, PrEP offers autonomy and empowerment for HIV prevention and can be recommended alongside antiretroviral therapy, fertility screening, vaginal self-insemination, intercourse timed to peak fertility, medically assisted reproduction, and other safer conception strategies to provide multiple options. The integration of PrEP into safer conception programs is warranted and will safely reduce HIV transmission to women, men, and children during the peri-conception period.

Antiretroviral combination use during pregnancy and the risk of major congenital malformations

OBJECTIVE

To quantify the risk of major congenital malformations (MCMs) associated with gestational combination antiretroviral use.

DESIGN

Population-based prospective cohort study.

METHODS

Using the Quebec Pregnancy Cohort from 1998 to 2015, we included women who were covered by the Quebec Drug Plan and had a singleton livebirth. All antiretroviral use alone or in combination were considered. MCMs overall and organ-specific malformations in the first year of life were identified.

RESULTS

In total, 214 240 pregnancies met inclusion criteria; 0.09% (n = 198) occurred while on antiretroviral combinations during the first trimester; 169 HIV-positive women without antiretroviral treatment were included. Compared with the general population in this cohort, the prevalence of MCMs was significantly higher in unexposed HIV-positive women (14.8 vs. 8.6%, P = 0.004) but not in antiretroviral-exposed HIV-positive women (10.3%, P = 0.41). Adjusting for potential confounders, including maternal HIV status, antiretroviral use during the first trimester was not associated with the risk of MCMs (adjusted odds ratio 0.59, 95% confidence interval 0.33-1.06). However, antiretroviral combination use during the first trimester was associated with an increased risk of defects of the small intestine (adjusted odds ratio 10.32, 95% confidence interval 2.85-37.38, P = 0.0004).

CONCLUSION

Antiretroviral therapy during the first trimester was not associated with the risk of overall MCMs but may be associated with an increased risk of defects of the small intestine. However, HIV-positive pregnant women who are not treated with antiretrovirals during pregnancy seem to have a higher risk of malformations; this is not seen among those who are treated, which could indicate that the underlying condition puts women at risk and not the treatment.

Antiretroviral therapy for pregnant women living with HIV or hepatitis B: a systematic review and meta-analysis

OBJECTIVE

To assess the impact of various antiretroviral/antiviral regimens in pregnant women living with HIV or hepatitis B virus (HBV).

DESIGN

We performed random effects meta-analysis for HIV-related outcomes and network meta-analysis for HBV outcomes, and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework to assess quality separately for each outcome.

DATA SOURCES

Embase and Medline to February 2017.

ELIGIBILITY CRITERIA

For maternal outcomes, we considered randomised controlled trials (RCTs) comparing tenofovir-based regimens with those with alternative nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). For child outcomes, we included RCTs and comparative observational studies of tenofovir-based regimens versus alternative NRTIs regimens or, for HBV, placebo.

RESULTS

Ten studies (seven RCTs) met the inclusion criteria for maternal and child outcomes, and an additional 33 studies (12 RCTs) met the inclusion criteria for HBV-specific outcomes. The most common comparison was tenofovir and emtricitabine versus zidovudine and lamivudine. There was no apparent difference between tenofovir-based regimens and alternatives in maternal outcomes, including serious laboratory adverse events (low certainty) and serious clinical adverse events (moderate certainty). There was no difference between NRTIs in vertical transmission of HIV: 1 more per 1000, 8 fewer to 10 more, low certainty; or vertical transmission of HBV: 7 fewer per 1000, 10 fewer to 38 more, moderate certainty. We found moderate certainty evidence that tenofovir/emtricitabine increases the risk of stillbirths and early neonatal mortality (51 more per 1000, 11 more to 150 more) and the risk of early premature delivery at <34 weeks (42 more per 1000, 2 more to 127 more).

CONCLUSIONS

Tenofovir/emtricitabine is likely to increase stillbirth/early neonatal death and early premature delivery compared with zidovudine/lamivudine, but certainty is low when they are not coprescribed with lopinavir/ritonavir. Other outcomes are likely similar between antiretrovirals.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42017054392.

Safety of oral tenofovir disoproxil fumarate-based HIV pre-exposure prophylaxis use in lactating HIV-uninfected women

INTRODUCTION

In settings where HIV is prevalent in heterosexual populations, pregnancy and postpartum breastfeeding periods can be associated with substantial HIV acquisition risk. Pre-exposure prophylaxis (PrEP) with daily oral tenofovir disoproxil fumarate (TDF)/emtricitabine is an attractive HIV prevention option for women who are lactating but data are limited on its safety during the lactation period. Areas covered: We provide a concise synthesis and summary of current evidence on the safety of TDF-based PrEP during breastfeeding. We conducted a review, searching Pubmed database and major PrEP conferences for primary studies with TDF-based PrEP exposure during postpartum breastfeeding. Expert opinion: TDF-based oral PrEP is an effective female-controlled HIV prevention option. There is evidence supporting the safety of TDF use for infant outcomes during breastfeeding in antiretroviral treatment regimens for HIV and hepatitis B virus, and more limited, but consistently safe, data from use of TDF as PrEP. The potential for risk is arguably outweighed for at-risk individuals by HIV prevention benefits, including indirect protection to the infant as a result of preventing HIV in the breastfeeding mother. As PrEP delivery is scaled up in heterosexual populations in high HIV prevalence settings and for at-risk persons in other settings, implementation science studies can provide a framework to increase the accrual of safety, acceptability, and use data related to PrEP during lactation.

Efficacy and safety of tenofovir disoproxil fumarate in preventing vertical transmission of hepatitis B in pregnancies with high viral load

This study was a meta-analysis of the literature on the efficacy and safety of tenofovir disoproxil fumarate (TDF) in preventing vertical transmission of hepatitis B in pregnancies with high viral load. Four observational studies and one randomized controlled trial involving 585 pregnant women and 595 newborns were included in the meta-analysis. TDF was more effective than the placebo in reducing vertical transmission in HBeAg-positive chronic hepatitis B (CHB) pregnancies with high serum HBV-DNA levels (OR = 0.21, 95% CI = 0.07–0.61) at 4–12 months, infant HBV DNA seropositivity at delivery (OR = 0.16, 95% CI = 0.07–0.37), and a severe flair in maternal alanine aminotransferase (ALT) levels (OR = 0.43, 95% CI = 0.19–0.95) during pregnancy. In addition, TDF showed more improvement in HBV DNA suppression at delivery (OR = 254.46, 95% CI = 28.39–2280.79). No significant differences were found in HBeAg seroconversion or ALT normalization; or in rates of cesarean section, emergent cesarean section, postpartum hemorrhage, prematurity, congenital malformations, or infant death. However, TDF induced more drug-related adverse events (OR = 2.33, 95% CI = 1.39–3.89) and elevated creatine kinase (CK) (OR = 9.56, 95% CI = 1.17–78.09) than in controls. The available evidence suggests that TDF is effective and safe in preventing vertical transmission of hepatitis B in pregnancies exhibiting a high viral load.

Delayed introduction of the birth dose of Hepatitis B vaccine in EPI programs in East Africa: a missed opportunity for combating vertical transmission of Hepatitis B

Vertical Transmission of hepatitis B virus is a major route through which children acquire Hepatitis B infection. Only 10 out of 47 countries in Africa, and none from East Africa; have implemented the WHO recommendation of introducing a birth-dose of hepatitis B vaccine in their EPI program. This article therefore examines the challenges as well as the opportunities that exists for the introduction of a birth-dose of hepatitis vaccine in the National Expanded Program for Immunization (EPI) program by countries in the East African Region. It explores probable health systems factors that have hindered the countries from introducing the birth dose of hepatitis B vaccine and proposes actions that countries can take to introduce the vaccine based on their context by drawing on the experience of some Asian countries.

Systematic review with meta-analysis: the efficacy and safety of tenofovir to prevent mother-to-child transmission of hepatitis B virus

BACKGROUND

Preventing mother to child transmission of chronic hepatitis B infection in the setting of a high maternal viral load is challenging. The idea has emerged from antepartum tenofovir treatment with combination immunoprophylaxis.

AIMS

To demonstrate the efficacy and safety of tenofovir to prevent mother to child transmission of hepatitis B virus.

METHODS

PubMed, EMBASE, and Cochrane databases were searched through August 16, 2016. Comparative trials of second or third trimester tenofovir administration vs. controls for patients with chronic hepatitis B infection and non-comparative case series assessing mother to child transmission rates and evaluating maternal and foetal safety outcomes were included.

RESULTS

Ten studies (one randomised controlled trial, four non-randomised controlled trials and five case series) that enrolled 733 women were included. The pooled results from comparative trials (599 pregnancies) showed that tenofovir significantly reduced the risk of infant hepatitis B surface antigen seropositivity by 77% (odds ratio=0.23, 95% confidence intervals=0.10-0.52, P=.0004) without heterogeneity (I² =0%). In the case series analysis (134 pregnancies), only two cases (1.5%) of mother to child transmission with extremely high maternal viral load and non-compliance to treatment were identified. Maternal and foetal safety parameters including congenital malformation and foetal death were re-assuring.

CONCLUSIONS

For pregnant women with high hepatitis B virus DNA levels, tenofovir administration in the second or third trimester can prevent mother to child transmission when combined with hepatitis B immunoglobulin and the hepatitis B vaccine. Tenofovir is safe and tolerable for both the mother and foetus.

Prospective interventional study of tenofovir in pregnancy to prevent vertical transmission of hepatitis B in highly viremic women

BACKGROUND

The risk of vertical transmission of hepatitis B virus (HBV) increases as maternal HBV DNA increase, despite serovaccination to newborns.

METHODS

From 1 July 2012 to 1 January 2016, all pregnant women in Lariboisiere Hospital, Paris, France, with HBV DNA of 5 log10 IU/ml and above were administered tenofovir from week 28 of pregnancy until delivery. HBV DNA was measured at months 1, 2 of tenofovir and at delivery. The newborns were serovaccinated, tested for hepatitis B surface antigen, hepatitis B core antibody (HBcAb)±HBV DNA, and hepatitis B surface antibody (HBsAb) when aged 9 months, and then 24 months. This study was registered in http://www.ClinicalTrials.gov (NCT02039362).

RESULTS

Thirty-one women gave birth to 37 newborns. Maternal HBV DNA at baseline was 8.23 log10 IU/ml and above in 12 pregnancies. The mean (median) HBV DNA were 4.4±1.2 (4.8), 3.3±1.7 (3.8), and 2.1±1.9 (2.0) log10 IU/ml at months 1, 2 of tenofovir and at delivery, respectively. Twenty-seven newborns were followed up: none of the 19 children aged 9 months or older was positive for hepatitis B surface antigen when aged 9 months; 14 children tested positive for HBcAb (probably transferred maternal antibodies, not found when aged 24 months) and for HBsAb without HBV DNA. Four of the 19 children showed HBsAb without HBcAb, the last being doubtful for HBcAb and HBsAb without HBV DNA. Eight newborns aged less than 9 months were not tested.

CONCLUSION

Tenofovir from week 28 of pregnancy to highly viremic HBV women plus serovaccination to newborns could prevent chronic and past infection.

Adverse effects of oral antiviral therapy in chronic hepatitis B

Oral nucleoside/nucleotide analogues (NAs) are currently the backbone of chronic hepatitis B (CHB) infection treatment. They are generally well-tolerated by patients and safe to use. To date, a significant number of patients have been treated with NAs. Safety data has accumulated over the years. The aim of this article is to review and update the adverse effects of oral NAs. NAs can cause class adverse effects (i.e., myopathy, neuropathy, lactic acidosis) and dissimilar adverse effects. All NAs carry a “Black Box” warning because of the potential risk for mitochondrial dysfunction. However, these adverse effects are rarely reported. The majority of cases are associated with lamivudine and telbivudine. Adefovir can lead to dose- and time-dependent nephrotoxicity, even at low doses. Tenofovir has significant renal and bone toxicity in patients with human immunodeficiency virus (HIV) infection. However, bone and renal toxicity in patients with CHB are not as prominent as in HIV infection. Entecavir and lamivudine are not generally associated with renal adverse events. Entecavir has been claimed to increase the risk of lactic acidosis in decompensated liver disease and high Model for End-Stage Liver Disease scores. However, current studies reported that entecavir could be safely used in decompensated cirrhosis. An increase in fetal adverse events has not been reported with lamivudine, telbivudine and tenofovir use in pregnant women, while there is no adequate data regarding entecavir and adefovir. Further long-term experience is required to highlight the adverse effects of NAs, especially in special patient populations, including pregnant women, elderly and patients with renal impairment.

Hepatitis B immunoglobulin during pregnancy for prevention of mother-to-child transmission of hepatitis B virus

BACKGROUND

Hepatitis is a viral infection of the liver. It is mainly transmitted between people through contact with infected blood, frequently from mother to baby in-utero. Hepatitis B poses significant risk to the fetus and up to 85% of infants infected by their mothers at birth develop chronic hepatitis B virus (HBV) infection. Hepatitis B immunoglobulin (HBIG) is a purified solution of human immunoglobulin that could be administered to the mother, newborn, or both. HBIG offers protection against HBV infection when administered to pregnant women who test positive for hepatitis B envelope antigen (HBeAg) or hepatitis B surface antigen (HBsAg), or both. When HBIG is administered to pregnant women, the antibodies passively diffuse across the placenta to the child. This materno-fetal diffusion is maximal during the third trimester of pregnancy. Up to 1% to 9% infants born to HBV-carrying mothers still have HBV infection despite the newborn receiving HBIG plus active HBV vaccine in the immediate neonatal period. This suggests that additional intervention such as HBIG administration to the mother during the antenatal period could be beneficial to reduce the transmission rate in utero.

OBJECTIVES

To determine the benefits and harms of hepatitis B immunoglobulin (HBIG) administration to pregnant women during their third trimester of pregnancy for the prevention of mother-to-child transmission of hepatitis B virus infection.

SEARCH METHODS

We searched the The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, Science Citation Index Expanded (Web of Science), SCOPUS, African Journals OnLine, and INDEX MEDICUS up to June 2016. We searched ClinicalTrials.gov and portal of the WHO International Clinical Trials Registry Platform (ICTRP) in December 2016.

SELECTION CRITERIA

We included randomised clinical trials comparing HBIG versus placebo or no intervention in pregnant women with HBV.

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently. We analysed dichotomous outcome data using risk ratio (RR) and continuous outcome data using mean difference (MD) with 95% confidence intervals (CI). For meta-analyses, we used a fixed-effect model and a random-effects model, along with an assessment of heterogeneity. If there were statistically significant discrepancies in the results, we reported the more conservative point estimate. If the two estimates were equal, we used the estimate with the widest CI as our main result. We assessed bias control using the Cochrane Hepato-Biliary Group suggested bias risk domains and risk of random errors using Trial Sequential Analysis (TSA). We assessed the quality of the evidence using GRADE.

MAIN RESULTS

All 36 included trials originated from China and were at overall high risk of bias. The trials included 6044 pregnant women who were HBsAg, HBeAg, or hepatitis B virus DNA (HBV-DNA) positive. Only seven trials reported inclusion of HBeAg-positive mothers. All 36 trials compared HBIG versus no intervention. None of the trials used placebo.Most of the trials assessed HBIG 100 IU (two trials) and HBIG 200 IU (31 trials). The timing of administration of HBIG varied; 30 trials administered three doses of HBIG 200 IU at 28, 32, and 36 weeks of pregnancy. None of the trials reported all-cause mortality or other serious adverse events in the mothers or babies. Serological signs of hepatitis B infection of the newborns were reported as HBsAg, HBeAg, and HBV-DNA positive results at end of follow-up. Twenty-nine trials reported HBsAg status in newborns (median 1.2 months of follow-up after birth; range 0 to 12 months); seven trials reported HBeAg status (median 1.1 months of follow-up after birth; range 0 to 12 months); and 16 trials reported HBV-DNA status (median 1.2 months of follow-up; range 0 to 12 months). HBIG reduced mother-to-child transmission (MTCT) of HBsAg when compared with no intervention (179/2769 (6%) with HBIG versus 537/2541 (21%) with no intervention; RR 0.30, TSA-adjusted CI 0.20 to 0.52; I² = 36%; 29 trials; 5310 participants; very low quality evidence). HBV-DNA reduced MTCT of HBsAg (104/1112 (9%) with HBV-DNA versus 382/1018 (38%) with no intervention; RR 0.25, TSA-adjusted CI 0.22 to 0.27; I² = 84%; 16 trials; 2130 participants; low quality evidence). TSA supported both results. Meta-analysis showed that maternal HBIG did not decrease HBeAg in newborns compared with no intervention (184/889 (21%) with HBIG versus 232/875 (27%) with no intervention; RR 0.68, TSA-adjusted CI 0.04 to 6.37; I² = 90%; 7 trials; 1764 participants; very low quality evidence). TSA could neither support nor refute this observation as data were too sparse. None of the trials reported adverse events of the immunoglobulins on the newborns, presence of local and systemic adverse events on the mothers, or cost-effectiveness of treatment.

AUTHORS' CONCLUSIONS

Due to very low to low quality evidence found in this review, we are uncertain of the effect of benefit of antenatal HBIG administration to the HBV-infected mothers on newborn outcomes, such as HBsAg, HBV-DNA, and HBeAg compared with no intervention. The results of the effects of HBIG on HBsAg and HBeAg are surrogate outcomes (raising risk of indirectness), and we need to be critical while interpreting the findings. We found no data on newborn mortality or maternal mortality or both, or other serious adverse events. Well-designed randomised clinical trials are needed to determine the benefits and harms of HBIG versus placebo in prevention of MTCT of HBV.

Tenofovir disoproxil fumarate safety for women and their infants during pregnancy and breastfeeding

OBJECTIVES

Pregnant/lactating women in some sub-Saharan Africa settings are at substantial risk of HIV acquisition and could benefit from preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF), but safety data in pregnancy/lactation are limited.

DESIGN

Systematic data review through August 2016.

METHODS

We reviewed research reports/conference abstracts with maternal/child adverse outcome data in HIV-infected and HIV-uninfected pregnant/lactating women receiving TDF alone or in combination with other drugs compared with non-TDF regimens.

RESULTS

In total, 26 articles in HIV-infected and seven in HIV-uninfected women were identified. No statistically significant differences were observed between TDF and comparison non-TDF regimens in pregnancy incidence, stillbirth/pregnancy loss, preterm delivery less than 37 weeks, low birth weight <2500/<1500 g, small for gestational age, birth defects, or infant (>14 days) or maternal mortality. One study reported significantly higher very preterm delivery (<34 weeks) and neonatal mortality with TDF versus non-TDF antiretroviral therapy (ART), but no significant difference between TDF ART and zidovudine/single-dose nevirapine. Most studies report normal infant linear growth; one study showed slightly lower, and one higher 1-year length-for-age z-score in TDF ART-exposed infants. No significant differences were reported in abnormal laboratory values or bone markers between TDF and non-TDF-exposed infants in four studies. Lower maternal bone mineral density was observed at 74 weeks postpartum in breastfeeding women on TDF ART compared with no ART in one study.

CONCLUSION

Given available safety data, there does not appear to be a safety-related rationale for prohibiting PrEP during pregnancy/lactation or for discontinuing PrEP in HIV-uninfected women receiving PrEP who become pregnant and are at continuing risk of HIV acquisition.

Telbivudine therapy for chronic hepatitis B: A journey to identify super-responders and to optimize treatment using the roadmap model

Hepatitis B virus (HBV) infection is one of the most serious health problems worldwide with a high risk for cirrhosis and liver cancer. Several antiviral agents have been approved for the treatment of chronic hepatitis B, leading to a rapid reduction in HBV DNA and normalization of serum alanine aminotransferase levels. Telbivudine, a potent inhibitor of HBV replication, has been shown to be well tolerated. Because of the emergence of drug resistance, optimization strategies for telbivudine therapy have been shown to improve patient responses. Optimal baseline characteristics in so-called super-responders have been used to predict the virological response. Baseline HBV DNA levels < 9 log₁₀ copies/mL (2 × 10⁸  IU/mL) or alanine aminotransferase levels of more than or equal to twofold the upper limit of normal in HBeAg-positive patients and HBV DNA < 7 log₁₀ copies/mL (2 × 10⁶  IU/mL) in HBeAg-negative patients were strong predictors for virological response. In addition, the roadmap model, based on early virological response at week 24 of therapy, is considered as a powerful tool to identify patients at risk of treatment failure (HBV DNA ≥ 300 copies/mL, i.e. 60 IU/mL) and to reduce the risk of antiviral resistance. When considering pre-treatment characteristics and on-treatment responses, telbivudine may provide physicians with a wide choice of options to effectively treat patients with chronic hepatitis B, especially those with or at risk of renal impairment, or women of childbearing age.

Hepatic flare after telbivudine withdrawal and efficacy of postpartum antiviral therapy for pregnancies with chronic hepatitis B virus

BACKGROUND AND AIM

The efficacy of telbivudine for breaking vertical transmission of hepatitis B virus has been well established. Data on the risk of postpartum flare after telbivudine withdrawal and efficacy of extended antiviral therapy after delivery are limited.

METHODS

Chronic hepatitis B virus-infected women who received telbivudine beginning at week 24 or 28 of gestation were enrolled and then followed up to 52 weeks postpartum. Virological and biochemical parameters were assessed.

RESULTS

Of the 241 women who finished 52 weeks of follow-up, 33.6% had elevated serum alanine aminotransferase (ALT) during pregnancy. Telbivudine administration resulted in ALT normalization in 85.2% before delivery. Compared with women having a normal ALT level throughout pregnancy, those with elevated ALT had a significantly higher rate of ALT flare after telbivudine withdrawal (25.0% vs 11.9%; χ²  = 4.273, P = 0.039). Multivariate analysis indicated that only ALT elevation during pregnancy correlated with postpartum flare after telbivudine withdrawal. Those women with elevated ALT during pregnancy continued antiviral treatment to 52 weeks postpartum and had a significantly higher HBeAg seroconversion rate (P = 0.001) and a notable decrease in HBsAg titers (P = 0.001).

CONCLUSION

It is safe for the majority of women to withdraw telbivudine after delivery, whereas exciting serological response encourages extended antiviral therapy for mother with ALT elevation during pregnancy.

Cost-effectiveness of quantitative hepatitis B virus surface antigen testing in pregnancy in predicting vertical transmission risk

BACKGROUND & AIMS

Vertical transmission of hepatitis B virus (HBV) can occur despite immunoprophylaxis in mothers with high HBV DNA levels (>5-7 log₁₀ IU/ml). Quantitative hepatitis B surface antigen (qHBsAg) testing could be used as a surrogate marker to identify high viral load carriers, but there is limited data in pregnancy. We conducted a prospective observational study to determine the cost-effectiveness and utility of qHBsAg as a valid surrogate marker of HBV DNA.

METHODS

Pregnant patients with chronic hepatitis B were recruited from a tertiary referral centre. HBV DNA levels and qHBsAg were assessed in the second to third trimester. Statistical analysis was performed by Spearman's rank correlation and student's t-test. The cost-effectiveness of qHBsAg as compared to HBV DNA testing was calculated.

RESULTS

Ninety nine women with 103 pregnancies, median age 32 years, 65% Asian, 23% African and 12% other [Hispanic, Caucasian] were enrolled. Overall, 23% (23/99) were HBV e Ag (HBeAg)-positive. A significant correlation between qHBsAg and HBV DNA levels was noted in HBeAg-positive patients (r = 0.79, P < 0.05) but not in HBeAg-negative patients (r = 0.17, P = 0.06). In receiver operating characteristic analysis, the optimal qHBsAg cut-off values for predicting maternal viraemia associated with immunoprophylaxis failure (i.e., HBV DNA ≥7 log₁₀ IU/ml) was 4.3 log₁₀ IU/ml (accuracy 98.7%, sensitivity 94.7%, specificity 94.4%) (95% CI, 97-100%, P < 0.05). Use of HBV DNA as compared to qHBsAg costs approximately $20 000 more per infection prevented.

CONCLUSION

In resource poor regions, qHBsAg could be used as a more cost-effective marker for high maternal viraemia, and indicate when anti-HBV nucleos/tide analogue therapy should be used to prevent HBV immunoprophylaxis failure.

Prophylaxis of vertical HBV infection

INTRODUCTION

An appropriate management of HBV infection is the best strategy to finally reduce the total burden of HBV infection. Mother-to-child transmission (MTCT) is responsible for more than one third of chronic HBV infections worldwide. Because HBV infection in infancy or early childhood often leads to chronic infection, appropriate prophylaxis and management of HBV in pregnancy is crucial to prevent MTCT.

AREAS COVERED

The prevention of HBV vertical transmission is a complex task and includes: universal HBV screening of pregnant women, administration of antivirals in the third trimester of pregnancy in women with high viral load and passive-active HBV immunoprophylaxis with hepatitis B vaccine and hepatitis B immune globulin in newborns of all HBV infected women.

EXPERT OPINION

Universal screening of pregnant women for HBV infection, early identification of HBV DNA level in HBV-infected mothers, maternal treatment with class B according to FDA antivirals and passive/active anti-HBV immunoprophylaxis to newborns of HBV-positive mothers are crucial strategies for reducing vertical HBV transmission rates. Consideration of caesarean section in order to reduce the risk of vertical HBV transmission should be recommend in HBV infected pregnant women with high viral load despite antiviral therapy or when the therapy in the third trimester of pregnancy is not available.

Cost-effectiveness of antiviral therapy during late pregnancy to prevent perinatal transmission of hepatitis B virus

Background. Hepatitis B virus (HBV) infections are perinatally transmitted from chronically infected mothers. Supplemental antiviral therapy during late pregnancy with lamivudine (LAM), telbivudine (LdT), or tenofovir (TDF) can substantially reduce perinatal HBV transmission compared to postnatal immunoprophylaxis (IP) alone. However, the cost-effectiveness of these measures is not clear.

Aim. This study evaluated the cost-effectiveness from a societal perspective of supplemental antiviral agents for preventing perinatal HBV transmission in mothers with high viral load (>6 log₁₀ copies/mL).

Methods. A systematic review and network meta-analysis were performed for the risk of perinatal HBV transmission with antiviral therapies. A decision analysis was conducted to evaluate the clinical and economic outcomes in China of four competing strategies: postnatal IP alone (strategy IP), or in combination with perinatal LAM (strategy LAM + IP), LdT (strategy LdT + IP), or TDF (strategy TDF + IP). Antiviral treatments were administered from week 28 of gestation to 4 weeks after birth. Outcomes included treatment-related costs, number of infections, and quality-adjusted life years (QALYs). One- and two-way sensitivity analyses were performed to identify influential clinical and cost-related variables. Probabilistic sensitivity analyses were used to estimate the probabilities of being cost-effective for each strategy.

Results. LdT + IP and TDF + IP averted the most infections and HBV-related deaths, and gained the most QALYs. IP and TDF + IP were dominated as they resulted in less or equal QALYs with higher associated costs. LdT + IP had an incremental $2,891 per QALY gained (95% CI [$932–$20,372]) compared to LAM + IP (GDP per capita for China in 2013 was $6,800). One-way sensitivity analyses showed that the cost-effectiveness of LdT + IP was only sensitive to the relative risk of HBV transmission comparing LdT + IP with LAM + IP. Probabilistic sensitivity analyses demonstrated that LdT + IP was cost-effective in most cases across willingness-to-pay range of $6,800 ∼ $20,400 per QALY gained.

Conclusions. For pregnant HBV-infected women with high levels of viremia, supplemental use of LdT during late pregnancy combined with postnatal IP for infants is cost-effective in China.

Hepatitis Vaccines

Viral hepatitis is a serious health problem all over the world. However, the reduction of the morbidity and mortality due to vaccinations against hepatitis A and hepatitis B has been a major component in the overall reduction in vaccine preventable diseases. We will discuss the epidemiology, vaccine development, and post-vaccination effects of the hepatitis A and B virus. In addition, we discuss attempts to provide hepatitis D vaccine for the 350 million individuals infected with hepatitis B globally. Given the lack of a hepatitis C vaccine, the many challenges facing the production of a hepatitis C vaccine will be shown, along with current and former vaccination trials. As there is no current FDA-approved hepatitis E vaccine, we will present vaccination data that is available in the rest of the world. Finally, we will discuss the existing challenges and questions facing future endeavors for each of the hepatitis viruses, with efforts continuing to focus on dramatically reducing the morbidity and mortality associated with these serious infections of the liver.

Management of mother-to-child transmission of hepatitis B virus: Propositions and challenges

Chronic hepatitis B virus (HBV) infection due to mother-to-child transmission (MTCT) during perinatal period remains an important global health problem. Despite standard passive-active immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine in neonates, up to 9% of newborns still acquire HBV infection, especially these from hepatitis B e antigen (HBeAg) positive mothers. Management of HBV infection in pregnancy still need to draw careful attention because of some controversial aspects, including the failure of passive-active immunoprophylaxis in a fraction of newborns, the effect and necessity of periodical hepatitis B immunoglobulin (HBIG) injection to the mothers, the safety of antiviral prophylaxis with nucleoside/nucleotide analogs, the benefit of different delivery ways, and the safety of breastfeeding. In this review, we highlight these unsettled issues of preventive strategies in perinatal period, and we further aim to provide an optimal approach to the management of preventing MTCT of HBV infection.

AISF position paper on liver disease and pregnancy

The relationship between liver disease and pregnancy is of great clinical impact. Severe liver disease in pregnancy is rare; however, pregnancy-related liver disease is the most frequent cause of liver dysfunction during pregnancy and represents a severe threat to foetal and maternal survival. A rapid differential diagnosis between liver disease related or unrelated to pregnancy is required in women who present with liver dysfunction during pregnancy. This report summarizes the recommendation of an expert panel established by the Italian Association for the Study of the Liver (AISF) on the management of liver disease during pregnancy. The article provides an overview of liver disease occurring in pregnancy, an update on the key mechanisms involved in its pathogenesis, and an assessment of the available treatment options. The report contains in three sections: (1) specific liver diseases of pregnancy; (2) liver disease occurring during pregnancy; and (3) pregnancy in patients with pre-existing chronic liver disease. Each topic is discussed considering the most relevant data available in literature; the final statements are formulated according to both scientific evidence and clinical expertise of the involved physicians, and the AISF expert panel recommendations are reported.

Managing HBV in pregnancy. Prevention, prophylaxis, treatment and follow-up: position paper produced by Australian, UK and New Zealand key opinion leaders

Hepatitis B during pregnancy presents unique management issues for both the mother and fetus. These include the lack of a current cohesive strategy for treatment and follow-up of mothers and their babies; the uncertain risk of postpartum HBV flares; the lack of randomised trial data on the safety and efficacy of antiviral treatment in pregnancy; the lack of head-to-head studies comparing different antivirals in pregnancy; and the lack of epidemiologic information regarding infection across different populations globally. This position paper provides a comprehensive review of the management of women with HBV infection prior to conception, throughout each stage of pregnancy and postpartum, as well as recommendations and clinical approaches for the follow-up of children born to infected mothers, based on available evidence in the literature and recommendations from international experts. Prevention of perinatal transmission is an important component of global efforts to reduce the burden of chronic HBV since vertical transmission is responsible for most of the chronic infection worldwide.