Hepatitis E and Pregnancy: An Unholy Alliance Unmasked from Kashmir, India

[Hepatitis E: Epidemiology, pathology and prevention]

Hepatitis E virus (HEV) is a major cause of acute hepatitis. HEV genotypes 1 and 2 are associated with oro-faecal epidemics and fulminant hepatitis in pregnant women. HEV genotypes 3 and 4 are a zoonosis transmitted by uncooked pork. Infection is usually spontaneously resolutive. Chronic hepatitis may occur in immunocompromised patients. Extrahepatic disease is also possible. Prevention is based on hygiene, especially in high-risk patients, and access to safe drinking water for all. A recombinant vaccine against HEV has been developed and is currently being validated by the WHO.

Global vaccination against hepatitis E virus: position paper from the European Society of Clinical Microbiology and Infectious Diseases Viral Hepatitis Study Group

SCOPE

Hepatitis E virus (HEV) is a significant global health issue, impacting both low- and middle-income countries and industrialized nations. HEV genotypes 1 and 2, primarily transmitted through contaminated water, are endemic in low- and middle-income countries, whereas genotypes 3 and 4 are zoonotically transmitted in industrialized regions. Acute HEV infection poses severe risks, particularly to pregnant women and immunocompromised individuals, whereas chronic HEV infection leads to serious complications in those with pre-existing liver disease and transplant recipients. The development of an HEV vaccine offers new prevention opportunities, though its availability and integration into global immunization programmes remain limited.

METHODS

This position paper was developed by the European Society of Clinical Microbiology and Infectious Diseases Viral Hepatitis Study Group through an extensive review of clinical data, safety profiles, efficacy, and immunogenicity of HEV vaccines. The study group focused particularly on high-risk and special populations, synthesizing global health insights and incorporating recommendations from the Strategic Advisory Group of Experts to formulate strategies for wider HEV vaccination use.

QUESTIONS ADDRESSED IN THE POSITION PAPER

The position paper evaluates the efficacy and safety of HEV vaccines in both general and special populations. It identifies key barriers to the integration of HEV vaccines into routine immunization programmes, including infrastructure limitations, costs, and vaccine accessibility. The paper also proposes strategies to overcome these challenges and improve vaccine distribution. Furthermore, it addresses ways to enhance public awareness and international cooperation to promote HEV vaccination efforts globally.

IMPLICATIONS

European Society of Clinical Microbiology and Infectious Diseases Viral Hepatitis Study Group recommends HEV vaccination for high-risk groups, including women of childbearing age, patients with chronic liver diseases, and immunosuppressed individuals. Prioritizing investments in vaccine logistics, integrating diagnostics, and educational outreach can enhance uptake.

Acute liver failure

Acute liver failure (ALF) is a life-threatening disorder characterised by rapid deterioration of liver function, coagulopathy, and hepatic encephalopathy in the absence of pre-existing liver disease. The cause of ALF varies across the world. Common causes of ALF in adults include drug toxicity, hepatotropic and non-hepatotropic viruses, herbal and dietary supplements, antituberculosis drugs, and autoimmune hepatitis. The cause of liver failure affects the management and prognosis, and therefore extensive investigation for cause is strongly suggested. Sepsis with multiorgan failure and cerebral oedema remain the leading causes of death in patients with ALF and early identification and appropriate management can alter the course of ALF. Liver transplantation is the best current therapy, although the role of artificial liver support systems, particularly therapeutic plasma exchange, can be useful for patients with ALF, especially in non-transplant centres. In this Seminar, we discuss the cause, prognostic models, and management of ALF.

Receipt of hepatitis E vaccine and fetal loss in rural Bangladesh: further analysis of a double-blind, cluster-randomised, controlled trial

BACKGROUND

Vaccination constitutes an attractive control measure for hepatitis E virus (HEV), a major cause of maternal and perinatal mortality globally. Analysis of pregnant participants in an effectiveness trial of the HEV vaccine HEV239 showed possible HEV239-associated fetal losses. We aimed to conduct a detailed analysis of this safety signal.

METHODS

In a double-blind, cluster-randomised trial, 67 villages in Matlab, Bangladesh, were randomly allocated (1:1) to two vaccine groups, in which non-pregnant women aged 16-39 years received either HEV239 (HEV239 group) or Hepa-B (a hepatitis B vaccine; control group). We implemented weekly surveillance for pregnancy detection, and follow-up of pregnancies once every 2 weeks, using physician-confirmed diagnoses to evaluate fetal loss outcomes (miscarriage [spontaneous abortion], stillbirth, and elective termination). Data from a parallel system of reproductive health surveillance in Matlab were used to clarify study diagnoses when necessary. Miscarriage was assessed only among participants whose first positive pregnancy test and vaccination date (for whichever dose was closest to the date of last menstrual period [LMP]) were before 20 weeks' gestation. We defined the following analysis periods of interest: from 90 days before the LMP until the pregnancy outcome (the proximal period); from the LMP date until the pregnancy outcome (the pregnancy period); from 90 days before the LMP until the LMP date (90 days pre-LMP period); and from enrolment until 90 days before the LMP (the distal period). Both Poisson and Cox regression models were used to assess the associations between receipt of HEV239 and fetal loss outcomes. The trial was registered with ClinicalTrials.gov (NCT02759991).

FINDINGS

Among the 19 460 non-pregnant participants enrolled in the trial, 5011 were identified as having pregnancies within 2 years following vaccination and met the criteria for analysis (2407 in the HEV239 group and 2604 in the control group). Among participants vaccinated in the proximal period and evaluated for miscarriage, miscarriage occurred in 54 (8·9%) of 607 in the HEV239 group and 32 (4·5%) of 719 in the control group (adjusted relative risk [aRR] 2·0 [95% CI 1·3-3·1], p=0·0009). Similarly, the risk of miscarriages was increased in the HEV239 group versus the control group among participants inadvertently vaccinated during pregnancy (22 [10·5%] miscarriages among 209 participants in the HEV239 group vs 14 [5·3%] of 266 in the control group; aRR 2·1 [95% CI 1·1-4·1], p=0·036) and among those vaccinated within 90 days pre-LMP (32 [8·0%] of 398 vs 18 [4·0%] of 453; 1·9 [1·1-3·2], p=0·013). No increased risk of miscarriage was observed in those who received HEV239 in the distal period (93 [5·6%] of 1647 vs 80 [4·5%] of 1773; 1·3 [0·8-1·9], p=0·295). Stillbirth and elective termination showed no increased risk among women administered HEV239 versus those administered Hepa-B in any of the analysis periods.

INTERPRETATION

HEV239 given shortly before or during pregnancy was associated with an elevated risk of miscarriage. This association poses a possible safety concern for programmatic use of HEV239 in women of childbearing age.

FUNDING

Research Council of Norway and Innovax.

Safety and effectiveness of a recombinant hepatitis E vaccine in women of childbearing age in rural Bangladesh: a phase 4, double-blind, cluster-randomised, controlled trial

BACKGROUND

Hepatitis E virus (HEV) leads to high mortality in pregnant women in low-income countries. We aimed to evaluate the safety of a HEV vaccine and its effectiveness in preventing hepatitis E during pregnancy.

METHODS

In this phase 4, double-blind, cluster-randomised trial, 67 villages in Matlab, Bangladesh, were randomised 1:1 to receive HEV239 (a recombinant HEV vaccine) or a control vaccine (Hepa-B, a hepatitis B vaccine), using block randomisation with random number tables and blocks of size eight, stratified by cluster population size. Eligible non-pregnant women (aged 16-39 years) were vaccinated intramuscularly on day 0, at 1 month, and at 6 months, and followed up for 2 years after the last immunisation. The primary endpoint was hepatitis E in the pregnant, per-protocol population (those who received all three doses within 2 days of the scheduled dates), while safety was a secondary endpoint, assessed in the intention-to-treat (ITT) population (participants who received at least one dose). Solicited adverse events were recorded for the first 7 days after each dose, and unsolicited events until 2 years after a participant's final dose. Pregnancy-related safety outcomes were assessed in the pregnant ITT population. This study is registered with ClinicalTrials.gov (NCT02759991).

FINDINGS

Between Oct 2, 2017, and Feb 28, 2019, 19 460 participants were enrolled and received either HEV239 (9478 [48·7%] participants, 33 clusters) or Hepa-B (9982 [51·3%] participants, 34 clusters), of whom 17 937 (92·2%) participants received three doses and 17 613 (90·5%) were vaccinated according to protocol (8524 [48·4%] in the HEV239 group and 9089 [51·6%] in the control group). No pregnant participants were confirmed to have hepatitis E in either treatment group. HEV239 showed a mild safety profile, similar to Hepa-B, with no difference in the proportion of solicited adverse events between groups and no severe solicited events. Pain was the most common local symptom (1215 [12·8%] HEV239 recipients and 1218 [12·2%] Hepa-B recipients) and fever the most common systemic symptom (141 [1·5%] HEV239 recipients and 145 [1·5%] Hepa-B recipients). None of the serious adverse events or deaths were vaccine related. Among pregnant participants, the HEV239 group had a higher risk of miscarriage (136 [5·7%] of 2407 pregnant participants) compared with the control group (102 [3·9%] of 2604; adjusted odds ratio 1·54 [95% CI 1·15-2·08]).

INTERPRETATION

The effectiveness of HEV239 in pregnant women remains uncertain. HEV239 was safe and well tolerated in non-pregnant women, but findings regarding miscarriage warrant further investigation.

FUNDING

Research Council of Norway; Innovax.

Hepatitis E associated determinants and diagnostic biomarkers during pregnancy and its prenatal consequences in Multan, Punjab tertiary care setting (Pakistan)

OBJECTIVE

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world. Hepatitis E infection is commonly widespread by the fecal oral routes and contaminated water. This study was designed to explore the prevalence and risk factors of hepatitis E infection in pregnant women of the Multan district, Pakistan.

METHODS

The study comprised of a total of 500 enrolled patients, among which, 105 pregnant females with hepatitis E infection fulfilled the criteria for anti-HEV antibodies. Pregnant women without significant complications and without hepatitis E infection were excluded from this study. Hepatic profile, complete blood count, coagulation markers, and standard protocol were also assessed for fetal maternal hemorrhage.

RESULTS

Our results showed that 105 patients (66.66%, CI 95%) had HEV infection with mean age 25±5 years. Serum bilirubin levels were increased in 74 patients (70.47%), aspartate transaminase was elevated > 200 IU/L in 71 patients (67.61%), alanine transaminase was above the 100 IU/L in 65 patients (245 IU/L), and low platelet counts were found in 45 patients (42.85%). Moreover, fetal distress cases were 9 (10.84%) and maternal distress cases were about 11 (13.25%). Fetal mortality cases were 39 (37.14%), and maternal mortality cases were about 22 (20.95%) due to hepatic comma, intravascular coagulation, and hepatic failure.

CONCLUSION

It was concluded that the prevalence of Hepatitis E during pregnancy is associated with high risk factors of unhygienic practices, blood transfusion, and noncompliance with universal infection control techniques. Maternal fatalities and fetal consequences were exacerbated by HEV infection.

Current perspectives of viral hepatitis

Viral hepatitis represents a major danger to public health, and is a globally leading cause of death. The five liver-specific viruses: Hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus, and hepatitis E virus, each have their own unique epidemiology, structural biology, transmission, endemic patterns, risk of liver complications, and response to antiviral therapies. There remain few options for treatment, in spite of the increasing prevalence of viral-hepatitis-caused liver disease. Furthermore, chronic viral hepatitis is a leading worldwide cause of both liver-related morbidity and mortality, even though effective treatments are available that could reduce or prevent most patients' complications. In 2016, the World Health Organization released its plan to eliminate viral hepatitis as a public health threat by the year 2030, along with a discussion of current gaps and prospects for both regional and global eradication of viral hepatitis. Today, treatment is sufficiently able to prevent the disease from reaching advanced phases. However, future therapies must be extremely safe, and should ideally limit the period of treatment necessary. A better understanding of pathogenesis will prove beneficial in the development of potential treatment strategies targeting infections by viral hepatitis. This review aims to summarize the current state of knowledge on each type of viral hepatitis, together with major innovations.

Discovery of Hepatitis E and Its Impact on Global Health: A Journey of 44 Years about an Incredible Human-Interest Story

The story of the discovery of hepatitis E originated in the late 1970s with my extreme belief that there was a hidden saga in the relationship between jaundice and pregnancy in developing countries and the opportunity for a massive epidemic of viral hepatitis, which hit the Gulmarg Kashmir region in November 1978. Based on data collected from a door-to-door survey, the existence of a new disease, epidemic non-A, non-B hepatitis, caused by a hitherto unknown hepatitis virus, was announced. This news was received by the world community with hype and skepticism. In the early 1980s, the world watched in awe as an extreme example of human self-experimentation led to the identification of VLP. In 1990, a cDNA clone from the virus responsible for epidemic non-A, non-B hepatitis was isolated. Over the years, we traversed three eras of ambiguity, hope, and hype of hepatitis E research and conducted several seminal studies to understand the biology of HEV and manifestations of hepatitis E. Many milestones have been reached on the long and winding road of hepatitis E research to understand the structure, biology, and diversity of the agent, changing the behavior of the pathogen in developed countries, and the discovery of a highly effective vaccine.

Effect of High Hydrostatic Pressure Processing and Holder Pasteurization of Human Milk on Inactivation of Human Coronavirus 229E and Hepatitis E Virus

In preterm infants, sterilized donor milk (DM) is frequently used for feeding when breast milk is lacking. Most human milk banks use the Holder pasteurization method (HoP) to ensure the microbiological safety of DM. However, this method degrades many bioactive factors and hormones. Recently, high hydrostatic pressure (HHP) processing, which preserves bioactive factors in human milk, has been proposed as an alternative method to ensure the safety of DM. Although HHP treatment has been shown to be effective for viral inactivation, the effect of HHP on viruses that may be present in the complex nutritional matrix of human milk has not yet been defined. In the present study, we compared the efficacy of two HHP protocols (4 cycles at 350 MPa at 38 °C designated as 4xHP350 treatment, and 1 cycle at 600 MPa at 20 °C designated as 1xHP600 treatment) with the HoP method on artificially virus-infected DM. For this purpose, we used human coronavirus 229E (HCoV-229E) and hepatitis E virus (HEV) as surrogate models for enveloped and non-enveloped viruses. Our results showed that HCoV-229E is inactivated by HHP and HoP treatment. In particular, the 4xHP350 protocol is highly effective in inactivating HCoV-229E. However, our results demonstrated a matrix effect of human milk on HCoV-229E inactivation. Furthermore, we demonstrated that HEV is stable to moderate pressure HHP treatment, but the milk matrix does not protect it from inactivation by the high-pressure HHP treatment of 600 MPa. Importantly, the complex nutritional matrix of human milk protects HEV from inactivation by HoP treatment. In conclusion, we demonstrated that HHP and HoP treatments do not lead to complete inactivation of both surrogate virus models, indicating that these treatments cannot guarantee total viral safety of donor milk.

Development and Characterization of Efficient Cell Culture Systems for Genotype 1 Hepatitis E Virus and Its Infectious cDNA Clone

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis globally. Genotype 1 HEV (HEV-1) is responsible for multiple outbreaks in developing countries, causing high mortality rates in pregnant women. However, studies on HEV-1 have been hindered by its poor replication in cultured cells. The JE04-1601S strain recovered from a Japanese patient with fulminant hepatitis E who contracted HEV-1 while traveling to India was serially passaged 12 times in human cell lines. The cell-culture-generated viruses (passage 12; p12) grew efficiently in human cell lines, but the replication was not fully supported in porcine cells. A full-length cDNA clone was constructed using JE04-1601S_p12 as a template. It was able to produce an infectious virus, and viral protein expression was detectable in the transfected PLC/PRF/5 cells and culture supernatants. Consistently, HEV-1 growth was also not fully supported in the cell culture of cDNA-derived JE04-1601S_p12 progenies, potentially recapitulating the narrow tropism of HEV-1 observed in vivo. The availability of an efficient cell culture system for HEV-1 and its infectious cDNA clone will be useful for studying HEV species tropism and mechanisms underlying severe hepatitis in HEV-1-infected pregnant women as well as for discovering and developing safer treatment options for this condition.

Epidemiology of Hepatitis E

Hepatitis E virus (HEV) is globally prevalent with relatively high percentages of anti-HEV immunoglobulin G-positive individuals in the populations of developing and developed countries. There are two distinct epidemiological patterns of hepatitis E. In areas with high disease endemicity, primarily developing countries in Asia and Africa, this disease is caused mainly by genotypes HEV-1 or HEV-2; both genotypes transmit predominantly through contaminated water and occur as either outbreaks or sporadic cases of acute hepatitis. The acute hepatitis has the highest attack rate in young adults and is particularly severe among pregnant women. In developed countries, sporadic cases of locally acquired HEV-3 or HEV-4 infection are observed. The reservoir of HEV-3 and HEV-4 is believed to be animals, such as pigs, with zoonotic transmission to humans. The affected persons are often elderly, and persistent infection has been well documented among immunosuppressed persons. A subunit vaccine has been shown to be effective in preventing clinical disease and has been licensed in China.

Predicting incidence of hepatitis E for thirteen cities in Jiangsu Province, China

Hepatitis E has placed a heavy burden on China, especially in Jiangsu Province, so accurately predicting the incidence of hepatitis E benefits to alleviate the medical burden. In this paper, we propose a new attentive bidirectional long short-term memory network (denoted as BiLSTM-Attention) to predict the incidence of hepatitis E for all 13 cities in Jiangsu Province, China. Besides, we also explore the performance of adding meteorological factors and the Baidu (the most widely used Chinese search engine) index as additional training data for the prediction of our BiLSTM-Attention model. SARIMAX, GBDT, LSTM, BiLSTM, and BiLSTM-Attention models are tested in this study, based on the monthly incidence rates of hepatitis E, meteorological factors, and the Baidu index collected from 2011 to 2019 for the 13 cities in Jiangsu province, China. From January 2011 to December 2019, a total of 29,339 cases of hepatitis E were detected in all cities in Jiangsu Province, and the average monthly incidence rate for each city is 0.359 per 100,000 persons. Root mean square error (RMSE) and mean absolute error (MAE) are used for model selection and performance evaluation. The BiLSTM-Attention model considering meteorological factors and the Baidu index has the best performance for hepatitis E prediction in all cities, and it gets at least 10% improvement in RMSE and MAE for all 13 cities in Jiangsu province, which means the model has significantly improved the learning ability, generalizability, and prediction accuracy when comparing with others.

Two mutations in the ORF1 of genotype 1 hepatitis E virus enhance virus replication and may associate with fulminant hepatic failure

Hepatitis E virus (HEV) infection in pregnant women has a high incidence of developing fulminant hepatic failure (FHF) with significant mortality. Multiple amino acid changes in genotype 1 HEV (HEV-1) are reportedly linked to FHF clinical cases, but experimental confirmation of the roles of these changes in FHF is lacking. By utilizing the HEV-1 indicator replicon and infectious clone, we generated 11 HEV-1 single mutants, each with an individual mutation, and investigated the effect of these mutations on HEV replication and infection in human liver cells. We demonstrated that most of the mutations actually impaired HEV-1 replication efficiency compared with the wild type (WT), likely due to altered physicochemical properties and structural conformations. However, two mutations, A317T and V1120I, significantly increased HEV-1 replication. Notably, these two mutations simultaneously occurred in 100% of 21 HEV-1 variants from patients with FHF in Bangladesh. We further created an HEV-1 A317T/V1120I double mutant and found that it greatly enhanced HEV replication, which may explain the rapid viral replication and severe disease. Furthermore, we tested the effect of these FHF-associated mutations on genotype 3 HEV (HEV-3) replication and found that all the mutants had a reduced level of replication ability and infectivity, which is not unexpected due to distinct infection patterns between HEV-1 and HEV-3. Additionally, we demonstrated that these FHF-associated mutations do not appear to alter their sensitivity to ribavirin (RBV), suggesting that ribavirin remains a viable option for antiviral therapy for patients with FHF. The results have important implications for understanding the mechanism of HEV-1-associated FHF.

Chirohepevirus from Bats: Insights into Hepatitis E Virus Diversity and Evolution

Homologs of the human hepatitis E virus (HEV) have been identified in more than a dozen animal species. Some of them have been evidenced to cross species barriers and infect humans. Zoonotic HEV infections cause chronic liver diseases as well as a broad range of extrahepatic manifestations, which increasingly become significant clinical problems. Bats comprise approximately one-fifth of all named mammal species and are unique in their distinct immune response to viral infection. Most importantly, they are natural reservoirs of several highly pathogenic viruses, which have induced severe human diseases. Since the first discovery of HEV-related viruses in bats in 2012, multiple genetically divergent HEV variants have been reported in a total of 12 bat species over the last decade, which markedly expanded the host range of the HEV family and shed light on the evolutionary origin of human HEV. Meanwhile, bat-borne HEV also raised critical public health concerns about its zoonotic potential. Bat HEV strains resemble genomic features but exhibit considerable heterogeneity. Due to the close evolutionary relationships, bat HEV altogether has been recently assigned to an independent genus, Chirohepevirus. This review focuses on the current state of bat HEV and provides novel insights into HEV genetic diversity and molecular evolution.

Induction of Hepatitis E Virus Anti-ORF3 Antibodies from Systemic Administration of a Muscle-Specific Adeno-Associated Virus (AAV) Vector

The hepatitis E virus (HEV) is a major global health problem, leading to large outbreaks in the developing world and chronic infections in the developed world. HEV is a non-enveloped virus, which circulates in the blood in a quasi-enveloped form. The quasi-envelope protects HEV particles from neutralising anti-capsid antibodies in the serum; however, most vaccine approaches are designed to induce an immune response against the HEV capsid. In this study, we explored systemic in vivo administration of a novel synthetic and myotropic Adeno-associated virus vector (AAVMYO3) to express the small HEV phosphoprotein ORF3 (found on quasi-enveloped HEV) in the musculature of mice, resulting in the robust and dose-dependent formation of anti-ORF3 antibodies. Neutralisation assays using the serum of ORF3 AAV-transduced mice showed a modest inhibitory effect on the infection of quasi-enveloped HEV in vivo, comparable to previously characterised anti-ORF3 antibodies used as a control. The novel AAVMYO3 capsid used in this study can serve as a versatile platform for the continued development of vector-based vaccines against HEV and other infectious agents, which could complement traditional vaccines akin to the current positive experience with SARS-CoV-2.