Community-Based Screening for Hepatitis B and C Infectivity Using Two Quantitative Antigens to Identify Endemic Townships.

Screening and linkage to care are essential to achieve viral hepatitis elimination before 2030. The accurate identification of endemic areas is important for controlling diseases with geographic aggregation. Viral activity drives prognosis of chronic hepatitis B and hepatitis C virus infection. This screening was conducted in Chiayi County from 2018-2019. All residents aged 30 years or older were invited to participate in quantitative HBsAg (qHBsAg) and HCV Ag screening. Among the 4010 participants (male:female = 1630:2380), the prevalence of qHBsAg and HCV Ag was 9.9% (396/4010) and 4.1% (163/4010), respectively. High-prevalence townships were identified, three for qHBsAg > 15% and two for HCV Ag > 10%. The age-specific prevalence of qHBsAg was distributed in an inverse U-shape with a peak (16.0%, 68/424) for subjects in their 40 s; for HCV, prevalence increased with age. Concentrations of qHBsAg < 200 IU/mL were found in 54% (214/396) of carriers. The rate of oral antiviral treatment for HCV was 75.5% (114/151), with subjects younger than 75 years tending to undergo treatment (85.6% vs. 57.4%, p < 0.001). QHBsAg and HCV Ag core antigens can reflect the concentration of the viral load, which serves as a feasible screening tool. Using quantitative antigen screening for hepatitis B and C in community-based screening, two hyperendemic townships were identified from an endemic county.

Prevalence of hepatitis B, C, and D virus infection in Haiti: A systematic review and meta-analysis.

Background: Viral hepatitis causes an important global health burden. In 2016, the World Health Assembly adopted an objective to globally eliminate this as a public health threat by 2030. However, significant gaps exist between countries in their progress. Haiti is the last country that has introduced infant hepatitis B vaccines into the routine immunization program in the Region of the Americas, and its schedule still does not incorporate birth dose vaccines. As the first step to raise awareness of viral hepatitis in this country, we conducted a systematic review and meta-analysis to estimate the prevalence of hepatitis B (HBV), C (HCV), and D (HDV) viruses in Haiti. Methods: We searched PubMed, EMBASE, Web of Science and Scopus for studies reporting the prevalence of HBV, HCV and HDV among Haitian, with no language restriction, published until November 30th, 2021. Prevalence was pooled via a random-effects meta-analysis using a generalized linear mixed model with the logit link. Results: Of 453 articles retrieved, 25 studies were included: 16 reported the prevalence of hepatitis B surface antigen (HBsAg), three for anti-HCV antibody, and six for both HBsAg and anti-HCV. No study was found for HDV prevalence. The pooled prevalence of HBsAg was 0.7% [95% confidence interval (CI): 0.3-1.4, I 2 = 77.7%] among children, 3.5% (95% CI: 2.8-4.4, I 2 = 93.2%) in the general adult population and 7.4% (95% CI: 4.0-13.3, I 2 = 83.9%) in high-risk adult population. The pooled prevalence of anti-HCV antibody was 0.9% (95% CI: 0.6-1.4, I 2 = 93.5%) among the general population and 1.4% (95% CI: 0.4-4.2, I 2 = 0.0%) in high-risk adult population. No study reported the prevalence of anti-HCV antibody exclusively in children. Interpretation: The prevalence of blood-borne hepatitis, particularly that of HBV, is substantial in Haiti. The introduction of birth dose hepatitis B vaccines and improving access to testing and treatment services should be urgently considered to meet the elimination goal. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022298081, identifier: PROSPERO (CRD42022298081).

[Sero-epidemiological characteristics of the hepatitis D virus infection among hepatitis B virus infected-patients at a single center in Xinjiang region].

Objective: To investigate the sero-epidemiological characteristics of the hepatitis D virus (HDV) infection among hepatitis B virus (HBV)-infected patients in Xinjiang region. Methods: A single-center cross-sectional analysis method was used to select 264 cases of hepatitis B virus infection who were hospitalized in the Center for Infectious Diseases and Liver Diseases of the First Affiliated Hospital of Xinjiang Medical University from August 2021 to January 2022. All patients were tested for HDV Ag, HDV IgM, HDV IgG, and HDV RNA. The infection status of hepatitis D virus was analyzed by grouping according to their clinical type, HBV viral load, and HBsAg level. A paired t-test was used for data with measurement data conforming to normal distribution. A paired rank sum test was used for data that did not conform to normal distribution before and after treatment. Results: A total of 36 cases (13.64%) and 26 cases (9.85%) were positive for HDV serological markers and HDV RNA. According to clinical type grouping, the positive rates of HDV serum markers in patients with chronic hepatitis B, hepatitis B-related cirrhosis, liver cancer, and liver failure were 13.46%, 12.43%, and 20.83%, respectively, and there was no statistically significant difference among the three groups (χ2=0.86, P=0.649). The positive rates of HDV RNA were 11.54%, 8.11%, and 20.83%, respectively, and there was no statistically significant difference among the three groups (χ2=4.015, P=0.134). According to HBV viral load grouping, the positive rates of HDV serum markers among patients with viral loads <20, 20-2 000, and >2 000 IU/ml were 17.15%, 7.81%, and 6.67%, respectively, and the difference was not statistically significant among the three groups (χ2=4.846, P=0.089). The positive rates of HDV RNA were 9.47%, 10.94%, and 10%, respectively, and the difference was not statistically significant among the three groups (χ2=0.113, P=0.945). According to HBsAg level grouping, the positive rates of HDV serum markers in HBsAg<0.05, 0.05~250, and >250 IU/ml were 14.29%, 16.67%, and 10.85%, respectively, and there was no statistically significance between the three groups (χ2=1.745, P=0.418). The positive rates of HDV RNA were 4.76%, 8.77%, and 11.63%, respectively, and there was no statistically significant difference among the three groups (χ2=1.221, P=0.543). Clinical outcome, disease course, HBV DNA, serological markers of viral hepatitis, routine blood test, biochemical indicators, coagulation function, and other laboratory indicators were compared between HDV serum marker and/or nucleic acid positive and negative patients, and there was no statistically significant difference (P>0.05). Conclusion: The positive rate of HDV serological markers and HDV RNA is 13.64% and 9.85%, respectively, at a single center in the Xinjiang region, and there is still a high HDV infection rate among the HBV-infected patients with low levels of viral load and HBsAg.

Evaluation of hepatitis E antigen kinetics and its diagnostic utility for prediction of the outcomes of hepatitis E virus genotype 1 infection.

HEV-Ag ELISA assay is a reliable diagnostic test in resource-limited areas. HEV genotype 1 (HEV-1) infections are either self-limited or progress to fulminant hepatic failure (FHF) and death if anti-HEV therapy is delayed. Limited data is available about the diagnostic utility of HEV Ag on HEV-1 infections. Herein wWe aimed to study the kinetics of HEV Ag during HEV-1 infections at different stages, i.e., acute HEV infection, recovery, and progression to FHF. Also, we evaluated the diagnostic utility of this marker to predict the outcomes of HEV-1 infections. Plasma of acute hepatitis E (AHE) patients were assessed for HEV RNA by RT-qPCR, HEV Ag, and anti-HEV IgM by ELISA. The kinetics of HEV Ag was monitored at different time points; acute phase of infection, recovery, FHF stage, and post-recovery. Our results showed that the level of HEV Ag was elevated in AHE patients with a significantly higher level in FHF patients than recovered patients. We identified a plasma HEV Ag threshold that can differentiate between self-limiting infection and FHF progression with 100% sensitivity and 88.89% specificity. HEV Ag and HEV RNA have similar kinetics during the acute phase and self-limiting infection. In the FHF stage, HEV Ag and anti-HEV IgM have similar patterns of kinetics which could be the cause of liver damage. In conclusion, the HEV Ag assay can be used as a biomarker for predicting the consequences of HEV-1 infections which could be diagnostically useful for taking the appropriate measures to reduce the complications, especially for high-risk groups.

Multimodal investigation of rat hepatitis E virus antigenicity: Implications for infection, diagnostics, and vaccine efficacy.

BACKGROUND & AIMS: Rat hepatitis E virus (Orthohepevirus species C; HEV-C1) is an emerging cause of viral hepatitis in humans. HEV-C1 is divergent from other HEV variants infecting humans that belong to Orthohepevirus species A (HEV-A). This study assessed HEV-C1 antigenic divergence from HEV-A and investigated the impact of this divergence on infection susceptibility, serological test sensitivity, and vaccine efficacy. METHODS: Immunodominant E2s peptide sequences of HEV-A and HEV-C1 were aligned. Interactions of HEV-C1 E2s and anti-HEV-A monoclonal antibodies (mAbs) were modeled. Recombinant peptides incorporating E2s of HEV-A (HEV-A4 p239) and HEV-C1 (HEV-C1 p241) were expressed. HEV-A and HEV-C1 patient sera were tested using antibody enzymatic immunoassays (EIA), antigen EIAs, and HEV-A4 p239/HEV-C1 p241 immunoblots. Rats immunized with HEV-A1 p239 vaccine (Hecolin), HEV-A4 p239 or HEV-C1 p241 peptides were challenged with a HEV-C1 strain. RESULTS: E2s sequence identity between HEV-A and HEV-C1 was only 48%. There was low conservation at E2s residues (23/53; 43.4%) involved in mAb binding. Anti-HEV-A mAbs bound HEV-C1 poorly in homology modeling and antigen EIAs. Divergence resulted in low sensitivity of commercial antigen (0%) and antibody EIAs (10-70%) for HEV-C1 diagnosis. Species-specific HEV-A4 p239/HEV-C1 p241 immunoblots accurately differentiated HEV-A and HEV-C1 serological profiles in immunized rats (18/18; 100%) and infected-patient sera (32/36; 88.9%). Immunization with Hecolin and HEV-A4 p239 was partially protective while HEV-C1 p241 was fully protective against HEV-C1 infection in rats. CONCLUSIONS: Antigenic divergence significantly decreases sensitivity of hepatitis E serodiagnostic assays for HEV-C1 infection. Species-specific immunoblots are useful for diagnosing HEV-C1 and for differentiating the serological profiles of HEV-A and HEV-C1. Prior HEV-A exposure is not protective against HEV-C1. HEV-C1 p241 is an immunogenic vaccine candidate against HEV-C1. LAY SUMMARY: Rat hepatitis E virus (HEV-C1) is a new cause of hepatitis in humans. Using a combination of methods, we showed that HEV-C1 is highly divergent from the usual cause of human hepatitis (HEV-A). This divergence reduces the capacity of existing tests to diagnose HEV-C1 and also indicates that prior exposure to HEV-A (via infection or vaccination) is not protective against HEV-C1.

Toll-Like Receptor 8 Agonist GS-9688 Induces Sustained Efficacy in the Woodchuck Model of Chronic Hepatitis B.

BACKGROUND AND AIMS: GS-9688 (selgantolimod) is an oral selective small molecule agonist of toll-like receptor 8 in clinical development for the treatment of chronic hepatitis B. In this study, we evaluated the antiviral efficacy of GS-9688 in woodchucks chronically infected with woodchuck hepatitis virus (WHV), a hepadnavirus closely related to hepatitis B virus. APPROACH AND RESULTS: WHV-infected woodchucks received eight weekly oral doses of vehicle, 1 mg/kg GS-9688, or 3 mg/kg GS-9688. Vehicle and 1 mg/kg GS-9688 had no antiviral effect, whereas 3 mg/kg GS-9688 induced a >5 log10 reduction in serum viral load and reduced WHV surface antigen (WHsAg) levels to below the limit of detection in half of the treated woodchucks. In these animals, the antiviral response was maintained until the end of the study (>5 months after the end of treatment). GS-9688 treatment reduced intrahepatic WHV RNA and DNA levels by >95% in animals in which the antiviral response was sustained after treatment cessation, and these woodchucks also developed detectable anti-WHsAg antibodies. The antiviral efficacy of weekly oral dosing with 3 mg/kg GS-9688 was confirmed in a second woodchuck study. The antiviral response to GS-9688 did not correlate with systemic GS-9688 or cytokine levels but was associated with transient elevation of liver injury biomarkers and enhanced proliferative response of peripheral blood mononuclear cells to WHV peptides. Transcriptomic analysis of liver biopsies taken prior to treatment suggested that T follicular helper cells and various other immune cell subsets may play a role in the antiviral response to GS-9688. CONCLUSIONS: Finite, short-duration treatment with a clinically relevant dose of GS-9688 is well tolerated and can induce a sustained antiviral response in WHV-infected woodchucks; the identification of a baseline intrahepatic transcriptional signature associated with response to GS-9688 treatment provides insights into the immune mechanisms that mediate this antiviral effect.

Reduced incidence of hepatitis C in 9 villages in rural Egypt: Progress towards national elimination goals.

BACKGROUND & AIMS: Egypt has a major HCV burden and a well established treatment programme, with an ambitious goal of HCV elimination. Our aim was to assess the impact of a comprehensive HCV prevention, test and treat programme on the incidence of new HCV infections in 9 villages in rural Egypt. METHODS: An HCV "educate, test and treat" project was implemented in 73 villages across 7 governorates in Egypt between 06/2015 and 06/2018. In 2018, in 9 of the villages we re-tested individuals who originally tested HCV antibody (HCV-Ab) and HBsAg negative using rapid diagnostic tests (RDTs); confirmatory HCV RNA testing was performed for positive cases. The incidence rate per 1,000 person-years (py) was calculated, and risk factors for incident HCV infections assessed through an interviewer-administered questionnaire in 1:3 age- and gender-matched cases and controls. RESULTS: Out of 20,490 individuals who originally tested HCV-Ab negative in the 9 villages during the 2015-2016 implementation of the "educate, test and treat" programme, 19,816 (96.7%) were re-tested in 2018. Over a median of 2.4 years (IQR 2.1-2.7), there were 19 new HCV infections all of which were HCV RNA positive (incidence rate 0.37/1,000 py) (95% CI 0.24-0.59). Compared to a previous estimate of incidence in the Nile Delta region (2.4/1,000 py) from 2006, there was a substantial reduction in overall incidence of new HCV infections. Exposures through surgery (odds ratio 51; 95% CI 3.5-740.1) and dental procedures (odds ratio 23.8; 95% CI 2.9-194.9) were significant independent predictors of incident infections. CONCLUSIONS: This is the first study to show a substantial reduction in incidence of new HCV infections in a sample of the general population in Egypt following attainment of high testing and treatment coverage. New infections were significantly associated with healthcare-associated exposures. LAY SUMMARY: Egypt has a major national HCV testing and treatment programme with the goal of eliminating HCV infection. We assessed the impact of a comprehensive HCV prevention, test and treat programme in 73 villages that achieved high coverage of testing and treatment on the subsequent incidence of new HCV infections in nine of the villages. We re-tested people who were previously HCV antibody negative and found that the rate of new HCV infections was greatly reduced compared to previous estimates. We also found that exposure through surgery and dental procedures were associated with these new infections. This highlights the importance of continued strengthening of infection control and prevention measures, alongside treatment scale-up.

No evidence of HEV genotype 1 infections harming the male reproductive system.

Extrahepatic disorders are recorded with hepatitis E virus (HEV) infection. The impact of HEV infection on the male reproductive system is a query. In this study, we retrospectively analyzed semen from infertile men and prospectively examined the semen from acute hepatitis E patients (AHE) for HEV markers. HEV RNA and HEV Ag were not detectable in the semen of infertile men nor the semen of AHE patients. Although HEV markers were detectable in the urine of patients infected with HEV-1, these markers were absent in their semen. There is no significant difference in the level of reproductive hormones between AHE patients and healthy controls. Semen analysis of AHE patients did not show a notable abnormality and there was no significant difference in the semen quality and sperm characteristics between AHE and healthy controls.

Role of Hepatitis E Virus Infection in North American Patients With Severe Acute Liver Injury.

INTRODUCTION: The aim of this study was to determine the role of hepatitis E virus (HEV) infection in a large cohort of prospectively enrolled patients with severe acute liver injury (ALI). METHODS: Serum samples from 594 consecutive adults enrolled between 2008 and 2018 in the US Acute Liver Failure Study Group ALI registry were tested for anti-HEV IgM and anti-HEV IgG levels. Those with detectable anti-HEV IgM underwent further testing for HEV RNA using real-time polymerase chain reaction. RESULTS: The median age of patients was 38 years; 41% were men and 72% Caucasian. Etiologies of ALI included acetaminophen hepatotoxicity (50%), autoimmune hepatitis (8.9%), hepatitis B virus (8.9%), and idiosyncratic drug-induced liver injury (7.9%). Overall, 62 patients (10.4%) were negative for anti-HEV IgM but positive for IgG, whereas only 3 men (0.5%) were positive for both anti-HEV IgM and IgG. These 3 cases were initially diagnosed as having indeterminate, HEV, and hepatitis B virus-related ALI. One of these patients had detectable HEV RNA genotype 3, and another anti-HEV IgM+ patient had detectable HEV antigens by immunohistochemistry on liver biopsy. On multivariate modeling, older (odds ratio: 1.99) and non-Caucasian subjects (odds ratio: 2.92) were significantly more likely to have detectable anti-HEV IgG (P < 0.0001). DISCUSSION: Acute HEV infection is an infrequent cause of ALI in hospitalized North American adults. The anti-HEV IgG+ patients were significantly older and more likely to be non-Caucasian. These data are consistent with other population-based studies that indicate exposure to HEV in the general US population is declining over time and might reflect a cohort effect.

Assessment of hepatitis E virus (HEV) in the edible goat products pointed out a risk for human infection in Upper Egypt.

Hepatitis E virus (HEV) infection is endemic in developed and developing countries. Although the seroprevalence of HEV among the Egyptians is high, the sources of HEV infection in Egypt are not completely identified. Zoonotic HEV transmission among Egyptians is underestimated. Recently, we detected HEV in the milk of cows, this suggests the possibility of HEV transmission through the ingestion of contaminated milk. However, the role of small ruminants especially the goats in HEV epidemiology in Egypt remains unclear. Herein, we screened HEV markers in the edible goat products, mainly the milk and liver and we assessed the risk factor for HEV infection to the goat owners. A total of 280 goat milk samples were collected from 15 villages in the Assiut governorate. Anti-HEV IgG and HEV Ag were detected in 7.14% and 1.8% of the samples, respectively. HEV RNA was detected in 2 milk samples, cladogram analysis revealed that the isolated viruses belonged to HEV-3 subtype 3a. One viral isolate showed high homology to HEV recently isolated from the cow milk in the same geographic area. The level of anti-HEV IgG and HEV Ag were comparable in the milk and matched blood samples. While the urine and stool of HEV seropositive goats tested negative for HEV markers. HEV RNA was also detectable in the fresh goat liver samples (n = 2) derived from HEV seropositive goats. Finally, we analyzed HEV seroprevalence in households (n = 5) that owned the seropositive goats and households (n = 5) that owned the seronegative goats. Interestingly, anti-HEV IgG was recorded in 80% of households owned and frequently consumed the products of HEV seropositive goats, while HEV markers were not detectable in the owners of the seronegative goats. In conclusion: Here, we report HEV in the milk and liver of goats distributed in the villages of Assiut governorate. Higher HEV seroprevalence was recorded in the households that owned the seropositive goats. Investigation of the goat products is pivotal to assess the risk factor of HEV transmission to villagers in the Assiut governorate.

Enhancing the antigenicity and immunogenicity of monomeric forms of hepatitis C virus E2 for use as a preventive vaccine.

The E2 glycoprotein of hepatitis C virus (HCV) is the major target of broadly neutralizing antibodies (bNAbs) that are critical for the efficacy of a prophylactic HCV vaccine. We previously showed that a cell culture-derived, disulfide-linked high-molecular-weight (HMW) form of the E2 receptor-binding domain lacking three variable regions, Δ123-HMW, elicits broad neutralizing activity against the seven major genotypes of HCV. A limitation to the use of this antigen is that it is produced only at low yields and does not have a homogeneous composition. Here, we employed a sequential reduction and oxidation strategy to efficiently refold two high-yielding monomeric E2 species, D123 and a disulfide-minimized version (D123A7), into disulfide-linked HMW-like species (Δ123r and Δ123A7r). These proteins exhibited normal reactivity to bNAbs with continuous epitopes on the neutralizing face of E2, but reduced reactivity to conformation-dependent bNAbs and nonneutralizing antibodies (non-NAbs) compared with the corresponding monomeric species. Δ123r and Δ123A7r recapitulated the immunogenic properties of cell culture-derived D123-HMW in guinea pigs. The refolded antigens elicited antibodies that neutralized homologous and heterologous HCV genotypes, blocked the interaction between E2 and its cellular receptor CD81, and targeted the AS412, AS434, and AR3 domains. Of note, antibodies directed to epitopes overlapping with those of non-NAbs were absent. The approach to E2 antigen engineering outlined here provides an avenue for the development of preventive HCV vaccine candidates that induce bNAbs at higher yield and lower cost.

Demonstration of real-time and accelerated stability of hepatitis E vaccine with a combination of different physicochemical and immunochemical methods.

Hepatitis E, which is caused by infection with hepatitis E virus (HEV), is a global health problem in both developed and developing countries. An efficacious hepatitis E vaccine was licensed (by China) in 2011 with a trade name of Hecolin®. The antigen contained in this vaccine is a truncated version of the sole capsid protein encoded by open reading frame 2, which is designated p239. In this study, the real-time and real-condition stability and accelerated stability of five lots of hepatitis E vaccine products at the end of the designated shelf life, were assessed by a well-established quality analysis platform. The protein integrity of p239 that was recovered from the vaccine lots was demonstrated using CE-SDS, LC-MS and MALDI-TOF MS. The particle characteristics of the recovered vaccine antigen were assessed by TEM and HPSEC. The immunogenicity of hepatitis E vaccines was assessed by a mouse potency assay, which is part of product release and stability testing. Several methods were employed to assess the antigenicity of vaccines with or without adjuvant dissolution. Specifically, the well-established methods of sandwich ELISA and surface plasma resonance (SPR)-based BIAcore were used with unique murine monoclonal antibodies. Most interesting, two 'dissolution-free' immunoassays were also used for in situ antigenicity assessment of the vaccines. In addition to the confirmation of vaccine stability at the end of expiry dating, i.e., after storage in recommended conditions (2-8 °C) for 36 months, the mouse potency assay and sandwich ELISA were used to assess the accelerated stability of prefilled syringes to demonstrate the feasibility of out-of-cold-chain storage. In summary, molecular and functional characterization confirmed the shelf life stability of the vaccine at the end of expiry dating and the feasibility of transporting the hepatitis E vaccine for a given period of time out of cold chains.

Establishment of a Highly Sensitive Assay for Detection of Hepatitis E Virus-Specific Immunoglobulins.

Hepatitis E, a liver disease caused by infection with the hepatitis E virus (HEV), is a worldwide emerging disease. The diagnosis is based on the detection of viral RNA and of HEV-specific immunoglobulins (Ig). For the latter, various assays are commercially available but still lack harmonization. In this study, a Luminex-based multiplex serological assay was established that measures the presence of total IgG, IgA, and IgM antibodies, targeting a short peptide derived from the viral E2 protein. For the validation, 160 serum samples with a known HEV serostatus were used to determine the assay cutoff and accuracy. Thereby, HEV IgG- and RNA-positive sera were identified with a sensitivity of 100% and a specificity of 98% (95% confidence interval [CI], 94% to 100%). Application of the assay by retesting 514 serum samples previously characterized with different HEV-IgG or total antibody tests revealed a high level of agreement between the assays (Cohen's kappa, 0.58 to 0.99). The established method is highly sensitive and specific and can be easily implemented in a multiplex format to facilitate rapid differential diagnostics with a few microliters of sample input.

Hepatitis E Virus (HEV) Open Reading Frame 2 Antigen Kinetics in Human-Liver Chimeric Mice and Its Impact on HEV Diagnosis.

BACKGROUND: Hepatitis E virus infection (HEV) is an emerging problem in developed countries. Diagnosis of HEV infection is based on the detection of HEV-specific antibodies, viral RNA, and/or antigen (Ag). Humanized mice were previously reported as a model for the study of HEV infection, but published data were focused on the quantification of viral RNA. However, the kinetics of HEV Ag expression during infection remains poorly understood. METHODS: Plasma specimens and suspensions of fecal specimens from HEV-infected and ribavirin-treated humanized mice were analyzed using HEV antigen-specific enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction analysis, density gradient analysis, and Western blotting. RESULT: Open reading frame 2 (ORF2) Ag was detected in both plasma and stool from HEV-infected mice, and levels increased over time. Contrary to HEV RNA, ORF2 Ag levels were higher in mouse plasma than in stool. Interestingly, ORF2 was detected in plasma from mice that tested negative for HEV RNA in plasma but positive for HEV RNA in stool and was detected after viral clearance in mice that were treated with ribavirin. Plasma density gradient analysis revealed the presence of the noninfectious glycosylated form of ORF2. CONCLUSION: ORF2 Ag can be used as a marker of active HEV infection and for assessment of the effect of antiviral therapy, especially when fecal samples are not available or molecular diagnostic tests are not accessible.

A Territorywide Prevalence Study on Blood-Borne and Enteric Viral Hepatitis in Hong Kong.

BACKGROUND: Viral hepatitis epidemiological data are important for the World Health Organization plan of eliminating viral hepatitis. We aimed to document the prevalence of viral hepatitis A to E in Hong Kong. METHODS: This community-based study was open to all Hong Kong Chinese citizens aged ≥18 years. Baseline data and risk factors were collected. Hepatitis A-E serology was measured, including hepatitis B e antigen, antibodies to hepatitis B e antigen, antibodies to hepatitis D, hepatitis B virus (HBV) DNA for hepatitis B surface antigen (HBsAg)-positive participants, and antibodies to hepatitis B surface antigen and antibodies to hepatitis B core antigen (anti-HBc) in HBsAg-negative participants. Hepatitis C virus (HCV) RNA and genotypes were determined in anti-HCV-positive participants. RESULTS: A total of 10 256 participants were recruited from February 2015 to July 2016. Overall HBsAg seroprevalence was 7.8% (95% confidence interval [CI], 7.3%-8.3%), which was reduced significantly with HBV vaccination (odds ratio, 0.15 [95% CI, .11-.21]). Among HBsAg-negative participants, anti-HBc seroprevalence increased from 5.4% (<26 years) to 60.1% (>65 years). No hepatitis D virus (HDV) cases were detected. Anti-HCV positivity was 0.5% (95% CI, .3%-.6%). Prevalence of antibodies to hepatitis A virus (anti-HAV) and hepatitis E virus (anti-HEV) was 65.2% (95% CI, 64.2%-66.1%) and 33.3% (95% CI, 32.4%-34.2%), respectively, and were influenced by age, family income, and being born in mainland China. CONCLUSIONS: HBV seroprevalence remained high despite universal vaccination. High anti-HBc seroprevalence underlines the potential issue of HBV reactivation during profound immunosuppression. HCV and HDV remained uncommon. Anti-HAV seroprevalence had decreased whereas anti-HEV seroprevalence had risen.

Diagnostic utility of hepatitis E virus antigen-specific ELISA versus PCR testing in a cohort of post liver transplant patients in a large university hospital.

BACKGROUND: Hepatitis E virus (HEV) is an important infectious agent causing acute and chronic disease. Chronic hepatitis E affects immunocompromised people and serological testing is neither reliable nor sufficient to infer whether a patient has infection; therefore HEV RNA testing is the only reliable diagnostic test presently available. An HEV antigen-specific ELISA test is commercially available but is not yet in clinical use. OBJECTIVES: 1) determine the prevalence of HEV infection in the Royal Free Hospital (RFH) liver transplant cohort; 2) compare the diagnostic utility of HEV antigen-detection against the current gold standard; 3) consider screening strategies for HEV infection in immunocompromised groups. STUDY DESIGN: The serum samples of 490 post liver transplant patients visiting the outpatient clinic at the RFH over an eight-month period were tested for HEV with both an HEV antigen-specific ELISA and HEV RNA test. RESULTS: The prevalence of HEV infection was 0.20% (95% CI 0.0%-1.1%). The specificity of the ELISA was 98.2% with a positive predictive value of 10.0%. There was one true positive HEV case, which was picked up correctly by the antigen-specific ELISA. These results were improved by incorporating a neutralisation step into further ELISA tests. CONCLUSIONS: The antigen-specific ELISA test gave no false negative results, supporting its utility as a screening tool. There was one true antigen positive result. Further investigation including cost analysis is indicated to determine the efficacy of HEV antigen-specific ELISA testing in a screening context and in the clinical investigation of HEV infection in immunocompromised patients.

Evaluation of a Hepatitis C Virus Core Antigen Assay in Plasma and Dried Blood Spot Samples.

Simplified, affordable tools to diagnose active hepatitis C virus (HCV) infection are needed to scale up treatment. This study evaluated the analytical performance of HCV core antigen (HCVcAg) detection in samples of plasma and dried venous blood spots (DBSs). Paired plasma and DBS samples were prepared from remnant diagnostic samples, and plasma HCV RNA and HCVcAg were quantified. Sensitivity and specificity for HCVcAg (>3 fmol/L) at two HCV RNA thresholds (≥15 and ≥3000 IU/mL) were calculated. Of 120 paired samples tested, 25 had nonquantifiable HCV RNA and 95 had quantifiable HCV RNA. The median HCV RNA level in plasma was 5.6 log10 IU/mL (interquartile range: 5.2 to 6.2). The median HCVcAg levels in plasma and DBS samples were 2.3 log10 fmol/L (interquartile range: 0.1 to 3.1) and 1.1 log10 fmol/L (interquartile range: 0.0 to 1.9), respectively. For diagnosing HCV RNA ≥3000 IU/mL, the sensitivity and specificity of HCVcAg in plasma were 97.7% (95% CI, 91%-100%) and 100% (95% CI, 87%-100%), respectively. The sensitivity and specificity of HCVcAg in DBS were 88.6% (95% CI, 80%-94%) and 97% (95% CI, 82%-100%), respectively. The data from this study demonstrate good sensitivity and specificity of HCVcAg in plasma at an HCV RNA threshold of ≥3000 IU/mL. The level of HCVcAg quantified in plasma was higher than that in DBS.

Toward Systematic Screening for Persistent Hepatitis E Virus Infections in Transplant Patients.

BACKGROUND: Persistent hepatitis E virus genotype 3 (HEV G3) infections affect solid organ transplant (SOT) recipients and hematopoietic stem cell transplant (HSCT) recipients, but the burden in these cohorts in the United Kingdom is unknown. We established an audit to determine the point prevalence of HEV viremia in SOT and HSCT patients in the United Kingdom and compare different testing approaches to inform screening strategies. METHODS: Between January 5, 2016, and September 21, 2016, 3044 patients undergoing therapeutic drug monitoring at a single transplant center were screened for HEV ribonucleic acid (RNA) in minipools. A total of 2822 patients who could be characterized included 2419 SOT patients, 144 HSCT patients and 259 patients with no available transplant history. HEV RNA-positive samples were characterized by serology and genomic phylogeny. HEV antigen (HEV-Ag) testing was performed on RNA-positive samples, 420 RNA-negative samples and 176 RNA-negative blood donor samples. RESULTS: Nineteen of 2822 patients were viremic with G3 HEV giving a prevalence of 0.67%. The median alanine aminotransferase was significantly higher in the HEV viremic patients (P < 0.0001); however, 2 viremic patients had an alanine aminotransferase value within the normal range at the time of screening. The HEV-Ag assay identified 18/19 viremic patients and all those patients with proven viremia longer than 4 weeks. CONCLUSIONS: Transplant recipients in the United Kingdom are at a low but significant risk of HEV infection. HEV-Ag detection could be an alternative to RNA detection where the goal is to identify established persistent HEV infection, particularly where expertise, facilities, or cost prohibit RNA testing.

Origin, antigenicity, and function of a secreted form of ORF2 in hepatitis E virus infection.

The enterically transmitted hepatitis E virus (HEV) adopts a unique strategy to exit cells by cloaking its capsid (encoded by the viral ORF2 gene) and circulating in the blood as "quasi-enveloped" particles. However, recent evidence suggests that the majority of the ORF2 protein present in the patient serum and supernatants of HEV-infected cell culture exists in a free form and is not associated with virus particles. The origin and biological functions of this secreted form of ORF2 (ORF2S) are unknown. Here we show that production of ORF2S results from translation initiated at the previously presumed AUG start codon for the capsid protein, whereas translation of the actual capsid protein (ORF2C) is initiated at a previously unrecognized internal AUG codon (15 codons downstream of the first AUG). The addition of 15 amino acids to the N terminus of the capsid protein creates a signal sequence that drives ORF2S secretion via the secretory pathway. Unlike ORF2C, ORF2S is glycosylated and exists as a dimer. Nonetheless, ORF2S exhibits substantial antigenic overlap with the capsid, but the epitopes predicted to bind the putative cell receptor are lost. Consistent with this, ORF2S does not block HEV cell entry but inhibits antibody-mediated neutralization. These results reveal a previously unrecognized aspect in HEV biology and shed new light on the immune evasion mechanisms and pathogenesis of this virus.

Development and evaluation of a rapid point-of-care test for detecting the hepatitis E virus antigen.

BACKGROUND: Hepatitis E virus (HEV)-caused acute viral hepatitis is a major threat to public health worldwide. Recently, an enzyme linked immunosorbent assay (ELISA) kit detecting the HEV antigen was reported to have good concordance with the HEV RNA load and showed good clinical performance. But the ELISA kits can barely satisfy the needs of community clinics. In this study, a fluorescent microbead-based immunoassay (FMIA) for detecting the HEV antigen was developed and evaluated. METHODS: A mouse anti-HEV monoclonal antibody (mAb) conjugated with fluorescent microbeads was used as capturing antibody and another mouse mAb was used as detection antibody. Overall, 150 serum samples were collected from HEV-infected patients (n = 50) and non-HEV cases (n = 100) to evaluate the performance of the FMIA. RESULTS: The FMIA results showed a strong linear correlation with the viral RNA load. The diagnostic sensitivity and specificity of the HEV antigen FMIA were 92.0% (46/50) and 100.0% (100/100), respectively, and the test was consistent (kappa = 0.937, p = 0.627) with the commercial HEV antigen ELISA. The FMIA also showed good consistency with the PCR results (kappa = 0.939, p = 0.134). CONCLUSIONS: As a rapid point-of-care (POC) test, a FMIA that is developed with acceptable performance is suitable for acute hepatitis E diagnosis, especially in developing countries and regions, because of its reduced time and simplified operation.