Hepatitis E should be a global public health priority: recommendations for improving surveillance and prevention

Genetic substructure and host-specific natural selection trend across vaccine-candidate ORF-2 capsid protein of hepatitis-E virus

Hepatitis E virus is a primary cause of acute hepatitis worldwide. The present study attempts to assess the genetic variability and evolutionary divergence among HEV genotypes. A vaccine promising capsid-protein coding ORF-2 gene sequences of HEV was evaluated using phylogenetics, model-based population genetic methods and principal component analysis. The analyses unveiled nine distinct clusters as subpopulations for six HEV genotypes. HEV-3 genotype samples stratified into four different subgroups, while HEV-4 stratified into three additional subclusters. Rabbit-infectious HEV-3ra samples constitute a distinct cluster. Pairwise analysis identified marked genetic distinction of HEV-4c and HEV-4i subgenotypes compared to other genotypes. Numerous admixed, inter and intragenotype recombinant strains were detected. The MEME method identified several ORF-2 codon sites under positive selection. Some selection signatures lead to amino acid substitutions within ORF-2, resulting in altered physicochemical features. Moreover, a pattern of host-specific adaptive signatures was identified among HEV genotypes. The analyses conclusively depict that recombination and episodic positive selection events have shaped the observed genetic diversity among different HEV genotypes. The significant genetic diversity and stratification of HEV-3 and HEV-4 genotypes into subgroups, as identified in the current study, are noteworthy and may have implications for the efficacy of anti-HEV vaccines.

Long-term efficacy of a recombinant hepatitis E vaccine in adults: 10-year results from a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Hepatitis E virus (HEV) is a frequently overlooked causative agent of acute hepatitis. Evaluating the long-term durability of hepatitis E vaccine efficacy holds crucial importance.

METHODS

This study was an extension to a randomised, double-blind, placebo-controlled, phase-3 clinical trial of the hepatitis E vaccine conducted in Dontai County, Jiangsu, China. Participants were recruited from 11 townships in Dongtai County. In the initial trial, a total of 112 604 healthy adults aged 16-65 years were enrolled, stratified according to age and sex, and randomly assigned in a 1:1 ratio to receive three doses of hepatitis E vaccine or placebo intramuscularly at month 0, month 1, and month 6. A sensitive hepatitis E surveillance system including 205 clinical sentinels, covering the entire study region, was established and maintained for 10 years after vaccination. The primary outcome was the per-protocol efficacy of hepatitis E virus vaccine to prevent confirmed hepatitis E occurring at least 30 days after administration of the third dose. Throughout the study, the participants, site investigators, and laboratory staff remained blinded to the treatment assignments. This study is registered with ClinicalTrials.gov (NCT01014845).

FINDINGS

During the 10-year study period from Aug 22, 2007, to Oct 31, 2017, 90 people with hepatitis E were identified; 13 in the vaccine group (0·2 per 10 000 person-years) and 77 in the placebo group (1·4 per 10 000 person-years), corresponding to a vaccine efficacy of 83·1% (95% CI 69·4-91·4) in the modified intention-to-treat analysis and 86·6% (73·0 to 94·1) in the per-protocol analysis. In the subsets of participants assessed for immunogenicity persistence, of those who were seronegative at baseline and received three doses of hepatitis E vaccine, 254 (87·3%) of 291 vaccinees in Qindong at the 8·5-year mark and 1270 (73·0%) of 1740 vaccinees in Anfeng at the 7·5-year mark maintained detectable concentrations of antibodies.

INTERPRETATION

Immunisation with this hepatitis E vaccine offers durable protection against hepatitis E for up to 10 years, with vaccine-induced antibodies against HEV persisting for at least 8·5 years.

FUNDING

National Natural Science Foundation of China, Fujian Provincial Natural Science Foundation, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, and the Fundamental Research Funds for the Central Universities.

Common and Potential Emerging Foodborne Viruses: A Comprehensive Review

Human viruses and viruses from animals can cause illnesses in humans after the consumption of contaminated food or water. Contamination may occur during preparation by infected food handlers, during food production because of unsuitably controlled working conditions, or following the consumption of animal-based foods contaminated by a zoonotic virus. This review discussed the recent information available on the general and clinical characteristics of viruses, viral foodborne outbreaks and control strategies to prevent the viral contamination of food products and water. Viruses are responsible for the greatest number of illnesses from outbreaks caused by food, and risk assessment experts regard them as a high food safety priority. This concern is well founded, since a significant increase in viral foodborne outbreaks has occurred over the past 20 years. Norovirus, hepatitis A and E viruses, rotavirus, astrovirus, adenovirus, and sapovirus are the major common viruses associated with water or foodborne illness outbreaks. It is also suspected that many human viruses including Aichi virus, Nipah virus, tick-borne encephalitis virus, H5N1 avian influenza viruses, and coronaviruses (SARS-CoV-1, SARS-CoV-2 and MERS-CoV) also have the potential to be transmitted via food products. It is evident that the adoption of strict hygienic food processing measures from farm to table is required to prevent viruses from contaminating our food.

Seroprevalence of hepatitis E virus (HEV) among male craft and manual workers in Qatar (2020-2021)

Background

The rapid growth of Qatar in the last two decades has attracted a large influx of immigrant craft and manual workers (CMWs) seeking employment in jobs associated with food handling, domestic service, and construction. Nearly 60 % of Qatar's population are expatriates CMWs, including many from hyperendemic countries for HEV. Thus, estimating the seroprevalence of HEV in Qatar and understanding its epidemiology is essential for public health efforts to control HEV transmission in Qatar.

Methods

Blood samples from 2670 CMWs were collected between 2020 and 2021. All samples were tested for HEV-IgG antibodies. Positive HEV-IgG samples were tested for HEV-IgM antibodies, and those positives were also tested for viral antigens using an HEV-Ag ELISA kit and HEV-RNA by RT-PCR to confirm current HEV infections.

Results

The seroprevalence of HEV-IgG was 27.3 % (729/2670; 95 % CI: 25.6-29.0). Of those HEV-IgG positive, 8.23 % (60/729; 95 % CI: 6.30-10.5) were HEV-IgM positive. Of the IgM-positive samples, 2 were HEV-RNA positive (3.39 %; 95 % CI: 0.40-11.7), and 1 was HEV-Ag positive (1.69 %; 95 % CI: 0.04-9.09). In addition, HEV-IgG seroprevalence was associated with age and nationality, with the highest seroprevalence in participants from Egypt (IgG 60.0 %; IgM 5.56 %), Pakistan (IgG 59.0 %; IgM 2.24 %), Nepal (IgG 29.3 %; IgM 2.70 %), Bangladesh (IgG 27.8 %; IgM 2.45 %), and India (IgG 23.9 %; IgM 2.43 %).

Conclusion

In this study, we showed that the seroprevalence of HEV among CMWs was slightly higher than what was previously reported among the urban population in Qatar (2013-2016).

Establishment of a robust rat hepatitis E virus fecal-oral infection model and validation for antiviral studies

The hepatitis E virus (HEV) is a major cause of hepatitis, with an estimated 3.3 million symptomatic cases annually. There is no HEV-specific treatment besides the off-label use of ribavirin and a vaccine is only available in China and Pakistan. To aid the development of therapeutic and preventive strategies, there is a need for convenient HEV infection models in small laboratory animals. To this end, we make use of the rat hepatitis E virus. Human infections with this virus have been reported in recent years, making it a relevant pathogen for the establishment of a small animal infection model. We here report that oral gavage of a feces suspension, containing a pre-defined viral RNA load, results in a reproducible synchronized infection in athymic nude rats. This route of administration mimics fecal-oral transmission in a standardized fashion. The suitability of the model to study the effect of antiviral drugs was assessed by using ribavirin, which significantly reduced viral loads in the feces, liver, and other tissues.

Orthohepevirus C infection as an emerging cause of acute hepatitis in Spain: First report in Europe

BACKGROUND & AIM

Hepatitis E virus (HEV) was considered the only member of the Hepeviridae family with zoonotic potential. Nevertheless, this consideration has been reassessed owing to several reported cases of acute and chronic hepatitis linked to the Orthohepevirus C genus. Because the circulation of Orthohepevirus C in rodents has been described worldwide, the risk of zoonotic transmission is plausibly global.

METHODS

Orthohepevirus C RNA was retrospectively evaluated in 2 cohorts of patients in Spain. The first cohort included patients with acute hepatitis without etiological diagnosis after screening for hepatotropic virus infection. The second cohort included patients diagnosed with acute HEV infection, defined as positivity for anti-HEV-IgM antibodies and/or detectable HEV RNA in serum.

RESULTS

Cohort 1 comprised 169 patients (64.4% male, median age 43 years) and cohort 2 comprised 98 individuals (68.3% male, median age 45 years). Of the individuals included in Cohort 1, two (1.18%; 95% CI 0.2-3.8) had detectable Orthohepevirus C RNA in serum. In Cohort 2, of the 98 included patients, 58 showed detectable HEV RNA, while 40 only showed positivity for IgM antibodies. Among those bearing only IgM antibodies, Orthohepevirus C RNA was detected in 1 (2.5%; 95% CI 0.06-13.1) individual. All strains were consistent with genotype C1. The infection resulted in mild self-limiting acute hepatitis in 2 patients. Infection caused severe acute hepatitis in the remaining patient who died as a result of liver and renal failure.

CONCLUSIONS

We described 3 cases of Orthohepevirus C in patients with acute hepatitis, resulting in the first description of this infection in Europe. The prevalence obtained in our study suggests that Orthohepevirus C could be an emerging disease in Europe.

LAY SUMMARY

We describe the first cases of acute hepatitis related to rat hepatitis E virus in Europe. The prevalence found in our study suggest that rat hepatitis E virus could be considered an emerging disease in Europe.

Clinical and Epidemiological Spectrum of Acute Viral Hepatitis Due to Hepatitis A and E in Children: A Descriptive, Cross-Sectional, Hospital-Based Study

Objective: Acute viral hepatitis (AVH) in children is a serious and major public health concern globally and in developing countries such as Pakistan. We conducted this study to determine the clinical and epidemiological spectrum of AVH due to hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in children.

Methodology: This cross-sectional study was conducted at the Pediatric Medicine Department of a tertiary care hospital from February 20, 2020, to February 20, 2022. A total of 200 children 1-12 years of age who presented with symptoms and signs of AVH were enrolled. Demographic and clinical characteristics were noted, and venous blood was drawn for the assessment of HAV IgM and HEV IgM using an enzyme-linked immunosorbent assay (ELISA). Descriptive statistics are run, and the results are presented as tables.

Results: Of the children, 75% were diagnosed with acute HAV infection. The median duration of illness was six days (range: 2-21 days). The most common age group affected was 6-10 years (43.5%), of which 56.5% were males. Most of the children belonged to low and middle socioeconomic status (86.5%), and 41.5% consumed underground water for drinking. Fever was the most common symptom, followed by appetite loss and yellow discoloration of urine. Alanine aminotransferase (ALT) was significantly high in HEV compared to HAV infection (2060.2±1036.7 versus 1730.7±957.5 IU/L) (P=0.04).

Conclusion: Acute HAV was more prevalent. Those who are male, 6-10 years of age, from lower and middle socioeconomic status, and using underground drinking water were more affected by acute viral hepatitis. The clinical and biochemical presentation of HAV and HEV did not differ significantly.

Changes and Clinical Significance of PIVKA-II in Hepatitis E Patients

Increased protein induced by vitamin K absence or antagonist-II (PIVKA-II) levels had been widely reported in patients with hepatocellular carcinoma (HCC) and chronic hepatitis. However, the role of PIVKA-II in hepatitis E is unclear. The aim of this study was to clarify the changes related with PIVKA-II and its clinical significance in hepatitis E. We enrolled 84 patients with hepatitis E hospitalized in two hospitals from December 2019 to June 2021. The levels of serum PIVKA-II and related serological indicators in the patients were determined to elucidate the role of PIVKA-II in hepatitis E. We observed that 59.51% (50/84) of patients showed an increase in PIVKA-II levels. Compared with the normal PIVKA-II group (<32 mAU/L), patients in the elevated PIVKA-II group (>32 mAU/L) had much higher serum total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), and total bile acid (TBA) levels (p < 0.05 for each). Compared with the slightly elevated PIVKA-II group (32–125 mAU/L), patients in the significantly elevated PIVKA-II group (>125 mAU/L) had much lower serum albumin, alanine aminotransferase (ALT), aspartate transaminase (AST) levels, and longer days for the hospital stay (p < 0.05 for each). The association of PIVKA-II with TBIL and DBIL was an inverted U-shaped curve with an inflection point at 199.1 mAU/L). The association of PIVKA-II with IBIL was a U-shaped curve with an inflection point at 18.6 mAU/L while the association of PIVKA-II with albumin was an inverted U-shaped curve with an inflection point at 18.6 mAU/L. With the improvement of the disease, PIVKA-II levels were gradually decreased and finally returned to normal. This trend was consistent with that of bilirubin, and a peak appeared in the third week. Therefore, findings from our study show that the increase in PIVKA-II levels can be related to the degree of hepatic insufficiency in patients with hepatitis E, wherein PIVKA-II levels are transiently increased, and the trend of change can be related to the disease course.

Immunization with recombinant ORF2 p551 protein protects common marmosets (Callithrix jacchus) against homologous and heterologous hepatitis E virus challenge

BACKGROUND

Hepatitis E virus (HEV) is a major causative agent of acute hepatitis worldwide, prompting continuous HEV vaccine efforts. Vaccine development is hampered by the lack of convenient animal models susceptible to infection with different HEV genotypes. We produced recombinant open reading frame 2 protein (pORF2; p551) of HEV genotype (GT) 3 and assessed its immunogenicity and protectivity against HEV challenge in common marmosets (Callithrix jacchus, CM).

METHODS

p551 with consensus sequence corresponding to amino acid residues 110-660 of HEV GT3 pORF2 was expressed in E. coli and purified by affinity chromatography. CMs were immunized intramuscularly with 20 μg of p551 VLPs with alum adjuvant (n = 4) or adjuvant alone (n = 2) at weeks 0, 3, 7 and 19. At week 27, p551-immunized and control animals were challenged with HEV GT1 or GT3 and thereafter longitudinally screened for markers of liver function, anti-HEV IgG and HEV RNA in feces and sera.

RESULTS

Purified p551 formed VLPs with particle size of 27.71 ± 2.42 nm. Two immunizations with p551 induced anti-HEV IgG mean titer of 1:1810. Immunized CMs challenged with homologous and heterologous HEV genotype did not develop HEV infection during the follow-up. Control CMs infected with both HEV GT1 and GT3 demonstrated signs of HEV infection with virus shedding and elevation of the levels of liver enzymes. High levels of anti-HEV IgG persisted in vaccinated CMs and control CMs that resolved HEV infection, for up to two years post challenge.

CONCLUSIONS

CMs are shown to be a convenient laboratory animal model susceptible to infection with HEV GT1 and GT3. Immunization with HEV GT3 ORF2/p551 triggers potent anti-HEV antibody response protecting CMs from homologous and heterologous HEV challenge. This advances p551 in VLPs as a prototype vaccine against HEV.

Relative risk factors for seropositive hepatitis E virus among blood donors and haemodialysis patients: The pivotal role of primary health care education

Background:

Hepatitis E virus is a zoonotic virus with a worldwide epidemic outbreak. The aim of the study was to identify relative risk factors and co-infections concerning the seropositive HEV IgG among blood donors and haemodialysis (HD) patients in the central blood bank and renal dialysis centre in Wad Medani city, Gezira State, Sudan.

Materials and Methods:

This was a cross-sectional study that included 600 participants, among them 180 showed strong seropositive HEV IgG. The structured questionnaire was used to collect data of the participants’ demographics, disease risk factors and HEV IgG co-infections with HBV, HCV, HIV and syphilis.

Results:

Among the 180 strong seropositive HEV IgG respondents, 84 were blood donors and 96 were haemodialysis patients. The gender and age (18–30 years) had a significant association with the virus exposure (P = 0.000, P = 0.000). Importantly, a significant association of HEV prevalence due to the localities effect exhibited with the highest rate among South Gezira (OR = 38, CI = 14.1–107; P = 0.000). This also observed in Wad Medani, Umm Algura, East Gezira and Managil localities (P = 0.000). The effect of the animal contact on HEV distribution exerted the significant association among the respondents for blood donors and haemodialysis patients in univariate (OR = 4.09, 95% CI 1.5–10.9; P = 0.005) and multivariate (OR = 3.2, CI = 1.1–9.4; P = 0.027) analysis.

Conclusion:

The relative risk factors of the HEV seroprevalence were gender, age, locality and animal contact. Besides the need of a regular survey for the virus seroprevalence, primary health care physicians can play pivotal role in health education, especially in rural areas of Sudan. In addition, primary health care physicians in Sudan are expected to establish strategies and plans to eradicate and minimise the health impact of HEV.