Hepatitis delta virus as a global health problem

Elimination of HDV: Epidemiologic implications and public health perspectives

Hepatitis delta virus (HDV) infection causes the severest form of viral hepatitis in humans. Discovered in 1977, it was considered an infection prevalent in the eastern Mediterranean region. Today it is recognized as a global infection of public health importance, however accurate prevalence remains uncertain because of lack of good epidemiological studies. Under-screening for HDV is the single most important factor in under-estimating the true burden of infection. Urgent efforts are therefore needed to apply reliable screening tools and robust surveillance methodologies to study HDV. There is now a move by major hepatology societies to recommend HDV antibody testing in all persons with HBV infection. Important differences also need to be recognized between countries considered endemic or non-endemic countries. While the endemic infections likely spread horizontally in the general population, and is quite often nosocomial, in non-endemic countries special populations may carry the greater burden, such as persons with injection drug use and various sexual exposures. Even in endemic countries, HDV often exists in significant pockets of the general population. HDV has been categorized as an orphan infection due to lack of approved therapies. Recently there have significant advances in therapy and further clinical trials continue. However, as new therapies are approved, equitable access to the medications will become a major public health issue, particularly because most HDV patients live in low or low middle income countries.

Hepatitis D virus infection in a large cohort of immigrants in southern Italy: a multicenter, prospective study

Background

Since few data are available in the literature on the prevalence of anti-Delta-positive subjects in immigrant populations, the aim of the present study was to evaluate the demographic and virological characteristics of HDV infection in a large cohort of immigrants living in southern Italy.

Methods

Between January 2012 and February 2020 all immigrants attending one of the 5 first- level centers were enrolled and screened for HBsAg, the HBsAg-positive for anti-Delta and if positive, for HDV-RNA and HDV genotype.

Results

Of the 3521 immigrants observed in the study period, 3417 (97.0%) agreed to be screened; they were mainly males (61%), with a median age of 27 years (IQR 8–74) and came prevalently (58%) from sub-Saharan Africa.

Of the 3417 patients enrolled, 319 (9%) subjects were HBsAg-positive, and of those, 8 (2.5%) were anti-Delta-positive. No difference in the demographic and epidemiological characteristics was observed between the anti-Delta-negative vs -positive. Of the 8 anti-Delta-positive subjects, only one was HDV-RNA-positive (viral load: 7050 IU/mL), genotype 1, with clinical signs of cirrhosis.

Conclusions

the present study showed a prevalence of HDV of 2.5% in a large cohort of asymptomatic immigrants, suggesting the need for screening campaigns for viral infections including delta hepatitis in this population.

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-022-01938-0.

Hepatitis D: advances and challenges

Hepatitis D virus (HDV) infection causes the most severe form of viral hepatitis with rapid progression to cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Although discovered > 40 years ago, little attention has been paid to this pathogen from both scientific and public communities. However, effectively combating hepatitis D requires advanced scientific knowledge and joint efforts from multi-stakeholders. In this review, we emphasized the recent advances in HDV virology, epidemiology, clinical feature, treatment, and prevention. We not only highlighted the remaining challenges but also the opportunities that can move the field forward.

HBV/HDV Co-Infection: Epidemiological and Clinical Changes, Recent Knowledge and Future Challenges

Several investigations have been published on Hepatitis Delta Virus (HDV) infection in recent years, from which we have drawn the salient data to provide readers with useful information to improve their knowledge on the subject. HDV genotypes 5–8 have been recently imported to Western countries from central Africa, whose clinical relevance deserves further investigation. Ongoing HDV replication has been identified as an independent predictor of progression to cirrhosis and HCC for patients with HDV chronic hepatitis (HDV-CH). Long-term treatments of HDV-CH with standard or pegylated interferon alfa (peg-IFN-α) have all been unsatisfactory, leading to a sustained virological response (SVR) only in 20–30% of patients treated, faced with a poor tolerability and frequent serious adverse reactions; the addition of HBV nucleo(s)tide analogues to peg-IFN- α did not improve the rate of SVR. The improved knowledge of the HDV life cycle has allowed the development of direct acting agents towards key-points of the HDV life cycle, namely bulevirtide, lonafarnib and nucleic acid polymers. Preliminary data have shown that these drugs are more effective than interferon-based therapies, but adverse reactions are also common, which however seem toned down in combination therapy with other antivirals.

Epidemiology, Natural History, and Treatment of Hepatitis Delta Virus Infection in HIV/Hepatitis B Virus Coinfection

PURPOSE OF REVIEW

Limited data exist on the prevalence, determinants, and outcomes of hepatitis delta virus (HDV) infection among HIV/hepatitis B virus (HBV)-coinfected persons. This review provides current evidence on the epidemiology, natural history, and treatment of HDV infection in patients with HIV/HBV coinfection and highlights future research needs.

RECENT FINDINGS

Cross-sectional studies in Europe, Africa, South America, and Asia show that the prevalence of HDV among HIV/HBV-coinfected patients ranges from 1.2 to 25%. No studies have evaluated the prevalence of HDV infection among HIV/HBV-coinfected patients in the USA. HDV infection increases the risk of hepatic decompensation and hepatocellular carcinoma among HIV/HBV-coinfected patients. HDV treatment remains limited to pegylated interferon-alpha, which results in sustained virologic response in fewer than 25%. Data on the epidemiology, natural history, and treatment of HDV among HIV/HBV-coinfected persons remain limited. More research is needed to address these knowledge gaps in order to better manage HDV coinfection in HIV/HBV-coinfected patients.

Molecular epidemiology and clinical characteristics of hepatitis delta virus (HDV) infected patients with elevated transaminases in Shanghai, China

BACKGROUND

Patients coinfected with HBV and hepatitis D virus (HDV) have a greater risk of HCC and cirrhosis. The current study was undertaken to assess HDV genotype distribution and determine clinical characteristics of hepatitis delta virus (HDV) among HBsAg positive individuals in Shanghai.

METHOD

This retrospective study involved 225 serum samples from HBsAg positive hospitalized patients from October 2010 to April 2013. HDV-specific RT-nested PCR was used to amplify HDV RNA. HDV genotypes were characterized by Next-generation sequencing (NGS), followed by phylogenetic analyses. HDV/HBV co-infected patients and HBV mono-infected patients were compared clinically and virologically.

RESULTS

Out of the 225 HBsAg-positive serum samples with elevated transaminases, HDV-RNA was identified in 11 (4.9%) patients. The HBV loads in the HDV positive group were significantly lower than the HDV negative HBV-infected patients. The aminotransferase enzymes were significantly higher in HDV/HBV co-infected compared to HDV negative patients (P < 0.05). Phylogenetic analyses indicated that HDV-2 genotype being the predominant genotype, other HDV genotypes were not observed. HDV/HBV patients were significantly associated with a rather unfavourable clinical outcome.

CONCLUSION

In summary, the prevalence of HDV infection in patients with elevated transaminases is not low and the predominance of HDV genotype 2 infection in Shanghai. This finding helps us to better understand the correlation of HDV/HBV co-infection. Moreover, Next-generation sequencing (NGS) technologies provide a rapid, precise method for generating HDV genomes to define infecting genotypes.

Phylodynamic and Phylogeographic Analysis of Hepatitis Delta Virus Genotype 3 Isolated in South America

The hepatitis delta virus (HDV) is a globally distributed agent, and its genetic variability allows for it to be organized into eight genotypes with different geographic distributions. In South America, genotype 3 (HDV-3) is frequently isolated and responsible for the most severe form of infection. The objective of this study was to evaluate the evolutionary and epidemiological dynamics of HDV-3 over the years and to describe its distribution throughout this continent in an evolutionary perspective. While using Bayesian analysis, with strains being deposited in the Nucleotide database, the most recent common ancestor was dated back to 1964 and phylogenetic analysis indicated that the dispersion may have started in Brazil, spreading to Venezuela and then to Colombia, respectively. Exponential growth in the effective number of infections was observed between the 1950s and 1970s, years after the first report of the presence of HDV on the continent, during the Labrea Black Fever outbreak, which showed that the virus continued to spread, increasing the number of cases decades after the first reports. Subsequently, the analysis showed a decrease in the epidemiological levels of HDV, which was probably due to the implantation of the vaccine against its helper virus, hepatitis B virus, and serological screening methods implemented in the blood banks.

An update on the management of chronic hepatitis D

Hepatitis D virus (HDV) infection is associated with severe liver-related morbidity and mortality. The prevalence of HDV is rising especially among people who abuse drugs and immigrants from endemic areas. Reliable diagnostic assays with enhanced sensitivity and specificity are essential for screening at-risk populations. Until recently, interferon has been the only treatment for hepatitis D. Its efficacy is, however, limited and it is associated with significant side effects. A number of novel antiviral agents that target various stages of the HDV life cycle show promising results. They are currently in different phases of clinical development. This review focuses on the changing epidemiology, novel therapeutic agents, and updated management of chronic hepatitis delta.

HDV infection in immigrant populations

AIMS

Little data have been published so far on the epidemiological aspects of hepatitis D virus (HDV) infection in immigrant populations and even poorer is the information on the virological, phylogenetic, and clinical aspects of this infection in these populations. This review article, aimed primarily at physicians caring for immigrants, summarizes the information available on HDV infection and analyzes data on this topic concerning the immigrant populations.

METHODS AND RESULTS

The prevalence of HDV infection in HBsAg-positive immigrants varies according to the country of origin. For example, in immigrants from sub-Saharan Africa, this prevalence is higher in those born in Equatorial Guinea (24.4%) than those from other African countries (10.3%). The epidemiological impact of HDV infection linked to migratory flows is a function of the different endemicity between countries of origin and countries in which a new existence has been established. This impact is high when immigrants from areas endemic to HDV infection (eg, Equatorial Guinea) settle in areas of low endemicity (eg, Germany or England, with a prevalence of around 4%), while the impact is lesser or nonexistent if the migratory flows are directed toward countries with intermediate endemicity (eg, Italy and Greece, with a prevalence of around 10%).

CONCLUSION

This impact of immigration on HDV epidemiology can be strong when HDV endemicity is high in the country of origin and low in the host country and slight when immigrants move to high or medium endemic countries.

The Epidemiology of Hepatitis D Virus in North Africa: A Systematic Review and Meta-Analysis

BACKGROUND

Hepatitis D virus (HDV) infection has been considered a serious neglected pandemic, particularly in developing countries. The virus causes a more severe disease than mono infection with hepatitis B virus (HBV). The epidemiology of HDV is not well documented in North Africa, which is known to be endemic for HBV. In this study, we explored the prevalence of HDV infection and also attempted to identify factors associated with hepatitis D positive status among chronic hepatitis B patients in North Africa.

METHODS

The electronic databases PubMed, Embase, Scopus, Science Direct, Web of Science, and Google Scholar were comprehensively searched for all papers published between January 1, 1998, and December 31, 2017, using appropriate strategies containing all related keywords, including North Africa, names of countries in the region, and all permutations of hepatitis D virus. The estimated prevalence of HDV in North Africa was calculated as an average of the pooled infection prevalence in each country weighted by the ratio of the country's hepatitis D virus population to the study's sample size in the survey data analysis.

FINDINGS

A total of 312 studies were identified and 32 were included in this study, with a total sample of 4907 individuals screened for HDV. There was considerable variability in the prevalence estimates of HDV within the countries of the region. The overall prevalence of HDV in the general population of North Africa was 5·01% (95% CI: 1·25-8·27) and in liver disease patients it was 20.7% (95% CI:9.87-44.53). Genotype-1 was the most prominent genotype reported in five published studies. Ten studies reported on HDV RNA in participants who were seropositive for HDV, and four studies highlighted the impact of demographic factors (sex and age). No study showed the impact of risk factors on the prevalence of HDV in North Africa.

INTERPRETATION

This review provides a comprehensive assessment of the burden of HDV in Northern Africa. There were significant differences in seroprevalence, study population, and diagnostic testing between the countries in the region. The results presented here will alert health professionals to implement clear policies based on evidence to diminish the burden of HDV infection. Such measures may include but are not restricted to improving the laboratory diagnostic tests and initiating patient data registries and blood screening. Further epidemiological and research studies are needed to explore the risk factors, coinfections, and approaches to increase testing for HDV, particularly in high-risk subpopulations, such as intravenous drug users and immigrants, and to define the consequences of HDV infection in North Africa.

Epidemiology and clinical outcomes of hepatitis delta (D) virus infection in Queensland, Australia

OBJECTIVES

To investigate the epidemiology, clinical characteristics and outcomes of those with hepatitis delta virus (HDV) infection in Queensland, Australia.

DESIGN

Retrospective cohort study of individuals tested for HDV between 1997 and 2016 in the public healthcare system in Queensland.

RESULTS

179 individuals recorded positive HDV serology between 1997 and 2016, with a total of 4407 individuals undergoing testing (seroprevalence 4.1%). The majority of HDV positive individuals were male and were born overseas. Those born in Africa had a higher risk ratio (RR) for HDV infection (RR, 1.55; 95% CI, 1.14-2.09); being born in Asia was associated with a relatively lower risk of HDV infection (RR, 0.36; 95% CI, 0.27-0.58). Positive hepatitis C virus (HCV) serology was significantly associated with positive HDV serology (RR, 2.98; 95% CI, 2.36-3.78). Of the HDV positive individuals born in Australia, the majority were HCV positive (69.8%). HDV positive individuals were less likely to be Hepatitis B e antigen (HBeAg) positive (RR, 0.64; 95% CI, 0.45-0.93) and recorded lower hepatitis B virus (HBV) viral loads. Positive HDV serology was associated with increased risk of liver cirrhosis (RR, 2.3; 95% CI 1.73-3.07) and liver transplantation (RR, 1.93; CI 1.31-2.85). Only 8% of HDV positive individuals underwent HDV treatment.

CONCLUSIONS

In Queensland, HDV seropositivity is associated with overseas birth, particularly in Africa. HDV infection is associated with decreased HBV viraemia and more advanced liver disease.

Clinical and virological heterogeneity of hepatitis delta in different regions world-wide: The Hepatitis Delta International Network (HDIN)

BACKGROUND & AIMS

Chronic hepatitis D (delta) is a major global health burden. Clinical and virological characteristics of patients with hepatitis D virus (HDV) infection and treatment approaches in different regions world-wide are poorly defined.

METHODS

The Hepatitis Delta International Network (HDIN) registry was established in 2011 with centres in Europe, Asia, North- and South America. Here, we report on clinical/ virological characteristics of the first 1576 patients with ongoing or past HDV infection included in the database until October 2016 and performed a retrospective outcome analysis. The primary aim was to investigate if the region of origin was associated with HDV replication and clinical outcome.

RESULTS

The majority of patients was male (n = 979, 62%) and the mean age was 36.7 years (range 1-79, with 9% of patients younger than 20 years). Most patients were HBeAg-negative (77%) and HDV-RNA positive (85%). Cirrhosis was reported in 48.7% of cases which included 13% of patients with previous or ongoing liver decompensation. Hepatocellular carcinoma (HCC) developed in 30 patients (2.5%) and 44 (3.6%) underwent liver transplantation. Regions of origin were independently associated with clinical endpoints and detectability of HDV RNA. Antiviral therapy was administered to 356 patients with different treatment uptakes in different regions. Of these, 264 patients were treated with interferon-a and 92 were treated with HBV-Nucs only.

CONCLUSIONS

The HDIN registry confirms the severity of hepatitis delta but also highlights the heterogeneity of patient characteristics and clinical outcomes in different regions. There is an urgent need for novel treatment options for HDV infection.

Development and performance of prototype serologic and molecular tests for hepatitis delta infection

Worldwide, an estimated 5% of hepatitis B virus (HBV) infected people are coinfected with hepatitis delta virus (HDV). HDV infection leads to increased mortality over HBV mono-infection, yet HDV diagnostics are not widely available. Prototype molecular (RNA) and serologic (IgG) assays were developed for high-throughput testing on the Abbott m2000 and ARCHITECT systems, respectively. RNA detection was achieved through amplification of a ribozyme region target, with a limit of detection of 5 IU/ml. The prototype serology assay (IgG) was developed using peptides derived from HDV large antigen (HDAg), and linear epitopes were further identified by peptide scan. Specificity of an HBV negative population was 100% for both assays. A panel of 145 HBsAg positive samples from Cameroon with unknown HDV status was tested using both assays: 16 (11.0%) had detectable HDV RNA, and 23 (15.7%) were sero-positive including the 16 HDV RNA positive samples. Additionally, an archival serial bleed panel from an HDV superinfected chimpanzee was tested with both prototypes; data was consistent with historic testing data using a commercial total anti-Delta test. Overall, the two prototype assays provide sensitive and specific methods for HDV detection using high throughput automated platforms, allowing opportunity for improved diagnosis of HDV infected patients.

Elevated serum β2-microglobulin in individuals coinfected with hepatitis B and hepatitis D virus in a rural settings in Southwest Nigeria

OBJECTIVE

Coinfection of hepatitis B virus (HBV) with hepatitis D virus (HDV) has being reported to increase severity of progression to hepatocellular carcinoma (HCC) and liver cirrhosis (LC). Beta microglobulin (2βM) which is present on the surfaces of blood cells in acceptable levels is a tumor marker which may become elevated in disease conditions. This study hence observed the prevalence of HBV and HDV coinfection in a rural population and their 2βM concentration.

RESULTS

Of the 368 samples, 66 (17.9%) were positive to hepatitis B surface antigen (HBsAg) and 33 (50%) were coinfected with HDV, 8 (2.1%) were monoinfected with HDV. 2βM concentration increased beyond the normal level in individuals coinfected with HBV and HDV as compared with the monoinfected individuals. Coinfection resulted in the increased concentration of 2βM in HBV and HDV coinfection and the likelihood of progression to HCC and LC may not be ruled out. Monoinfection with HDV also had high 2βM concentration but this is due to having being infected with a non-detected HBV or chronic infection in which HBV is clearing.

Hepatitis delta: virological and clinical aspects

There are an estimated 400 million chronic carriers of HBV worldwide; between 15 and 20 million have serological evidence of exposure to HDV. Traditionally, regions with high rates of endemicity are central and northern Africa, the Amazon Basin, eastern Europe and the Mediterranean, the Middle East and parts of Asia. There are two types of HDV/HBV infection which are differentiated by the previous status infection by HBV for the individual. Individuals with acute HBV infection contaminated by HDV is an HDV/HBV co-infection, while individuals with chronic HBV infection contaminated by HDV represent an HDV/HBV super-infection. The appropriate treatment for chronic hepatitis delta is still widely discussed since it does not have an effective drug. Alpha interferon is currently the only licensed therapy for the treatment of chronic hepatitis D. The most widely used drug is pegylated interferon but only approximately 25% of patients maintain a sustained viral response after 1 year of treatment. The best marker of therapeutic success would be the clearance of HBsAg, but this data is rare in clinical practice. Therefore, the best way to predict a sustained virologic response is the maintenance of undetectable HDV RNA levels.

The serological markers of acute infection with hepatitis A, B, C, D, E and G viruses revisited

Viral hepatitis is a liver infection caused by one of the six hepatitis viruses: hepatitis A, B, C, D, E, and G virus (HAV to HEV and HGV). These agents differ in their biological, immunological, pathological and epidemiological characteristics. They cause infections that, when symptomatic, lead to clinical manifestations and laboratory findings that are not specific to a particular virus, often making differential diagnosis difficult, especially when no knowledge is available regarding the patient's medical history or the epidemiological background. A number of acute-phase serological markers, such as anti-HAV, anti-HBc, anti-HDV and anti-HEV IgM antibodies, are able to provide a clear indication of an infection caused by HAV, HBV, HDV or HEV. Anti-HCV antibodies and HGV/RNA are used for the diagnosis of HCV and HGV infections. The importance of each of these markers will be reviewed, and different factors that can interfere with the diagnosis of acute infections caused by these viruses will be described.

Hepatitis delta-associated mortality in HIV/HBV-coinfected patients

BACKGROUND & AIMS

Hepatitis delta virus (HDV) infection accelerates the progression of hepatitis B virus (HBV)-related liver disease. We assessed the epidemiological characteristics of HDV infection in the nationwide Swiss HIV Cohort Study and evaluated its impact on clinical outcomes.

METHODS

All HIV-infected patients with a positive hepatitis B surface antigen test were considered and tested for anti-HDV antibodies. HDV amplification and sequencing were performed in anti-HDV-positive patients. Demographic and clinical characteristics at initiation of antiretroviral therapy, as well as causes of death were compared between HDV-positive and HDV-negative individuals using descriptive statistics. Kaplan-Meier and multivariable Cox regression analyses were used to evaluate the association between HDV infection and overall mortality, liver-related mortality as well as incidence of hepatocellular carcinoma (HCC).

RESULTS

Of 818 patients with a positive hepatitis B surface antigen tests, 771 (94%) had a stored serum sample available and were included. The prevalence of HDV infection was 15.4% (119/771, 95% CI: 12.9-18.0) and the proportion of HDV-positive patients with HDV replication 62.9% (73/116). HDV-infected patients were more likely to be persons who inject drugs (60.6% vs. 9.1%) and to have a positive hepatitis C virus (HCV) serology (73.1% vs. 17.8%) compared to HDV-uninfected ones. HDV infection was strongly associated with overall death (adjusted hazard ratio 2.33, 95% CI 1.41-3.84), liver-related death (7.71, 3.13-18.97) and with the occurrence of HCC (9.30, 3.03-28.61). Results were similar when persons who inject drugs or HCV-coinfected patients were excluded from the analyses.

CONCLUSIONS

The prevalence of HDV in hepatitis B surface antigen-positive patients in the Swiss HIV Cohort Study (SHCS) is high and HDV infection is independently associated with mortality and liver-related events, including HCC.

LAY SUMMARY

Hepatitis delta virus (HDV) infection accelerates the progression of hepatitis B virus (HBV)-related liver disease. In a nationwide cohort of HIV-infected individuals in Switzerland, 15% of HBV-coinfected patients had antibodies to HDV infection, of which a majority had active HDV replication. HDV-infected individuals were 2.5 times more likely to die, eight times more likely to die from a liver-related cause and nine times more likely to develop liver cancer compared to HDV-uninfected ones. Our results emphasize the need for prevention programs (including HBV vaccination), the systematic screening of at risk populations as well as close monitoring, and underline the importance of developing new treatments for chronic HDV infection.

Hepatitis D in Children

Hepatitis D virus (HDV) is an uncommon, defective, single-stranded circular RNA virus that is dependent on the hepatitis B virus' surface antigen envelope proteins for transmission. It is highly pathogenic and associated with high rates of progression to cirrhosis and associated complications. HDV continues to ravage endemic parts of Asia and Europe, and its prevalence in the United States, although low, has not decreased in frequency, despite universal hepatitis B virus vaccination, because of lack of testing and underrecognition. There are few reports on the prevalence and characteristics of HDV infection in the pediatric population. We present 2 patients with HDV infection at our institution; both were from eastern Europe and were treated with pegylated interferon-α. The present standard of care treatment for HDV yields suboptimal results, but insights into the virology of hepatitis D are stimulating the search for novel therapeutic approaches, particularly the development of prenylation inhibitors and viral entry inhibitors.

Oral prenylation inhibition with lonafarnib in chronic hepatitis D infection: a proof-of-concept randomised, double-blind, placebo-controlled phase 2A trial

BACKGROUND

Therapies for chronic hepatitis delta virus (HDV) infection are unsatisfactory. Prenylation is essential for HDV and inhibition abrogates HDV production in experimental models. In a proof-of-concept study, we aimed to assess the effect on HDV RNA levels, safety, and tolerability of the prenylation inhibitor lonafarnib in patients with chronic delta hepatitis.

METHODS

In this phase 2A double-blind, randomised, placebo-controlled study, patients aged 18 years or older with chronic HDV infection were randomly assigned (3:1 in group 1 and 2:1 in group 2) to receive lonafarnib 100 mg (group 1) or lonafarnib 200 mg (group 2) twice daily for 28 days with 6 months' follow-up. Participants were randomised by random-number tables blocked in groups of four without stratification. Both groups enrolled six treatment participants and two placebo participants. Group 1 placebo patients received open-label lonafarnib as group 2 participants. The primary therapeutic endpoint was a decrease in HDV RNA viral titre in serum and the primary safety endpoint was the ability to tolerate the drug at the prescribed dose for the full 4-week duration, defined as drug discontinuation due to intolerance or grade 3/4 adverse events. This trial is registered with ClinicalTrials.gov, number NCT01495585.

FINDINGS

Between Jan 19, 2012, and April 28, 2014, 14 patients were enrolled, of whom eight were assigned to group 1 and six were assigned to group 2. At day 28, compared with placebo, mean log HDV RNA declines from baseline were -0·73 log IU/mL in group 1 (95% CI 0·17-1·31; p=0·03) and -1·54 log IU/mL in group 2 (1·21-1·93; p<0·0001). Lonafarnib serum concentrations correlated with HDV RNA change (r(2)=0·78, p<0·0001). Model fits show that hepatitis B surface antigen (HBsAg) remained stable after a short pharmacological delay (0·75 days [SE 0·24]), lonafarnib effectiveness in blocking HDV production was greater in group 2 than in group 1 (0·952 [SE 0·06] vs 0·739 [0·05], p<0·001), and the HDV half-life was 1·62 days (0·07). There was no evidence of virological resistance. Adverse events were mainly mild to moderate with group 1 patients experiencing diarrhoea in three patients (50%) and nausea in two patients (33%) and in group 2 with all patients (100%) experiencing nausea, diarrhoea, abdominal bloating, and weight loss greater than 2 kg (mean of 4 kg). No treatment discontinuations occurred in any treatment groups.

INTERPRETATION

Treatment of chronic HDV with lonafarnib significantly reduces virus levels. The decline in virus levels significantly correlated with serum drug levels, providing further evidence for the efficacy of prenylation inhibition in chronic HDV.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute, National Institutes of Health, and Eiger Biopharmaceuticals Inc.

Hepatitis D Virus: Introduction and Epidemiology

Hepatitis D is caused by the hepatitis D virus (HDV), a unique RNA pathogen that requires the hepatitis B surface antigen (HBsAg) to infect. Hepatitis D is transmitted by the parenteral route. The main susceptible group is patients with chronic HBsAg infection who become superinfected with the virus. Hepatitis D occurs throughout the globe, but control of hepatitis B virus (HBV) in the last two decades has consistently diminished the circulation of HDV in industrialized countries. However, hepatitis D remains a medical issue for injecting drug users (IDUs), as well as immigrants from endemic HDV areas, who are reintroducing the infection in Europe.

Characterization of the Genotypic Profile of Hepatitis Delta Virus: Isolation of HDV Genotype-1 in the Western Amazon Region of Brazil

The hepatitis delta virus (HDV) is a hepatotropic subvirus that is dependent on the hepatitis B virus (HBV) and supplies the viral envelope containing the surface antigen of hepatitis B. Viral genetic diversity is related to the geographical origin of the isolates, and there are at least eight genotypes that are referred to as HDV-1 through HDV-8. HDV-3 is responsible for epidemics of severe and fulminant hepatitis, which are common in northeastern South America. HDV-3 is prevalent in the Brazilian Amazon and is associated with the increased aggressiveness of HDV infections. Although isolated, the characteristics of the clinical presentation of HDV-1 in the Amazon region have not yet been clearly reported.

OBJECTIVE

This study aims to assess the genotypic and clinical characteristics of individuals with the HDV-1 genotype in the western Amazon region.

METHODS

The HDV was genotyped by nested PCR-RFLP and sequencing from serum samples of 56 patients with HBV/HDV infection. The genotypes were correlated with the clinical characteristics presented by patients with HBV/HDV infection.

RESULTS

A prevalence of 92.3% for the HDV-3 genotype (n = 48) and 7.6% (n = 4) for the HDV-1 genotype was observed.

CONCLUSION

To date, this is the most extensive clinical study of HDV-1 genotype infections in the nonindigenous population of Western Amazonia.

Hepatitis B virus epidemiology

The epidemiology of hepatitis B virus (HBV) infection is geographically diverse, with population prevalence, age and mode of acquisition, and likelihood of progression to chronic infection mutually interdependent. The burden of chronic HBV infection is increasingly being recognized, with cirrhosis and liver cancer attributable to HBV continuing to increase. The outcomes of chronic HBV infection are affected by a range of factors, including viral genotype, the presence of coinfections with other blood-borne viruses, and the impact of other causes of liver disease. The increased recognition of HBV infection as a leading cause of death globally has resulted in the development of new structures and policies at the international level; immediate attention to implementing these strategies is now required.

Prevalence of hepatitis D virus infection among hepatitis B virus-infected individuals in India

BACKGROUND

The prevalence of hepatitis D virus (HDV) infection among persons with hepatitis B virus (HBV) infection shows geographic variation and has declined in recent times in several regions. In India, studies during the 1990s showed highly variable anti-HDV prevalence rates among HBV-infected persons; however, data using molecular testing and recent data are not available. We therefore studied the prevalence of HDV infection in HBV-infected patients using tests for anti-HDV and HDV ribonucleic acid (RNA).

METHODS

Two cohorts of patients with HBV infection were enrolled (cohort A, n = 150, January to December 2012; cohort B, n = 168, October 2013 to April 2014). Sera from cohort A were tested for IgG anti-HDV using three enzyme immunoassays and those from cohort B for IgG anti-HDV using an enzyme immunoassay and for HDV RNA using a real-time amplification assay.

RESULTS

Of the 318 subjects (259 male; mean age 36.9 years), 161 (50.6 %) had chronic hepatitis B, 101 (31.8 %) had cirrhosis, 52 (16.3 %) had acute viral hepatitis, and 4 (1.3 %) had acute liver failure. In cohort A, all specimens tested negative for anti-HDV antibodies using all the three assays. In cohort B, all specimens tested negative for anti-HDV IgG as well as HDV RNA.

CONCLUSION

Our data indicate that HDV infection is uncommon in northern India.

Long-term therapy of chronic delta hepatitis with peginterferon alfa

BACKGROUND

Chronic delta hepatitis virus (HDV) infection rapidly progresses to cirrhosis. Treatment with peginterferon for up to 2 years is often without durable response.

AIM

To examine the efficacy and safety of long-term peginterferon in achieving a durable response.

METHODS

Treatment was initiated with 180 μg/week of peginterferon alfa-2a with titration to a maximal tolerable dose, for up to 5 years. Liver biopsies and hepatic venous pressure gradients (HVPG) were evaluated at baseline, 1, 3 and 5 years. The primary endpoint was histological improvement or loss of serum HDV and HBsAg at 3 years.

RESULTS

Thirteen patients were treated for a median of 140 weeks (6-260) with an average peginterferon dose of 180 μg/week (90-270). At baseline, most had advanced disease (median Ishak fibrosis = 3) with portal hypertension (HVPG = 10.2 ± 6 mmHg). Five of 13 patients (39%) achieved the primary endpoint, with three seroconverting for HBsAg after 24, 37 and 202 weeks of treatment. Histological inflammation improved after 1 year, (median HAI: 10 vs. 7, P = 0.01) with persistence in 4/5 patients at 3 years (median HAI: 7.5). Greatest improvements occurred in the first year. Baseline bilirubin and HBsAg levels were significantly lower in virological responders than nonresponders. After 12 weeks, virological responders had a significant decline in HBsAg (1.5 log10 IU/mL, P = 0.05).

CONCLUSION

Despite increased doses and duration of therapy, treatment of chronic HDV with peginterferon remains unsatisfactory. Quantitative measures of HBsAg may be an important biomarker of early response to peginterferon therapy in chronic delta hepatitis virus infection.

Hepatitis delta: epidemiology, diagnosis and management 36 years after discovery

With recent studies showing increased prevalence of hepatitis delta (HDV) even in the US, Australia, and some countries in Europe, and very high prevalence in endemic regions, HDV infection is far from being a disappearing disease. Although immigrants from endemic countries have been shown to have increased risk, studies have clearly shown that the disease is not solely appearing in traditional high-risk groups. Recent studies provide increasing evidence that sexual transmission may be an important factor in HDV infection spread. Based on the totality of evidence showing increased disease progression and substantially increased risk of cirrhosis in HDV-infected CHB patients, and the current studies showing higher than expected prevalence, it is time to call for HDV screening of all CHB patients. HDV viral load detection and measurement should be considered in all patients whether or not they are anti-HDV-positive. With universal screening of CHB patients for HDV, earlier diagnosis and consideration of treatment would be possible. Current treatment of HDV is IFN-based therapy with or without HBV antivirals, but current research indicates the possibility that prenylation inhibitors, entry inhibitors, HBsAg release inhibitors, or other therapies currently in the pipeline may provide more effective therapy in the future. In addition, universal screening would serve the important public health goal of allowing patients to be educated on their status and on the need for HDV-negative patients to protect themselves against superinfection and for HDV-infected patients to protect against transmission to others. Further studies and global awareness of HDV infection are needed.

Hepatitis delta: the rediscovery

Hepatitis D is returning to western Europe through immigration. The clinical presentation recapitulates the typical features of a florid hepatitis D. Hepatitis D is also being rediscovered in the developing world and in the United States. Hepatitis D virus (HDV) remains endemic in many countries and efforts are underway to map the infection at local levels and improve the medical alert to hepatitis D. In the United States it is generally thought that HDV has gone and hepatitis D is no longer a problem. Awareness of hepatitis D in the country has recently been revived.

Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease

INTRODUCTION

A decline in hepatitis D virus (HDV) occurrence was described in Europe and Asia. We estimated HDV prevalence in the Brazilian Amazon following hepatitis B vaccination.

METHODS

This is a cross-sectional survey of HDV measured by total antibodies to HDV (anti-HD T).

RESULTS

HDV prevalence was 41.9% whiting HBsAg carries and was associated with age (PR = 1.96; 95% CI 1.12-3.42; p = 0.01), hepatitis B virus (HBV) infection (PR = 4.38; 95% CI 3.12-6.13; p < 0.001), and clinical hepatitis (PR =1.44; 95% CI 1.03-2.00; p = 0.03). Risk factors were related to HDV biology, clinical or demographic aspects such as underlying HBV infection, clinical hepatitis and age.

CONCLUSIONS

Our study demonstrated that HDV infection continues to be an important health issue in the Brazilian Amazon and that the implementation of the HBV vaccination in rural Lábrea had little or no impact on the spread of HDV. This shows that HDV has not yet disappeared from HBV hyperendemic areas and reminding that it is far from being a vanishing disease in the Amazon basin.

Hepatitis delta: on soft paws across Germany

INTRODUCTION

Globally, more than 350 million people are considered to be chronic carriers of the hepatitis B virus (HBV) infection; thereof, 15-20 million of these individuals are thought to be coinfected with hepatitis delta virus (HDV). The clinical course depends on the mode of transmission; whereas coinfection commonly resolves, superinfection aggravates the disease and progresses to chronicity in over 90 % of the cases, which, again, results in cirrhosis.

OBJECTIVE

Although many tests are performed in HBV carriers, data on the prevalence of anti-HDV-IgG in Germany are only rarely available and outdated. Therefore, we retrospectively evaluated the seroprevalence of anti-HDV-IgG from the results of our routine service.

MATERIALS AND METHODS

Between January 2000 and October 2011, serum samples from 2,844 patients (carrying hepatitis B surface antigen) admitted to University Hospital Frankfurt am Main, Frankfurt, Germany, were tested for anti-HDV-IgG by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The overall seroprevalence of anti-HDV-IgG in the collective of Frankfurt (n = 2,844) is 7.4 % [95 % confidence interval (CI): 6.4-8.4]. The amount of seropositive men (8.3 %, 95 % CI: 6.9-10) significantly exceeds the female proportion (5.7 %, 95 % CI: 4.3-7.5). The rate of seropositivity to anti-HDV-IgG in this collective of Frankfurt reached a maximum in the year 2003 (10.1 %, 95 % CI: 8.9-11.1). The lowest rate was observable in 2004, where 5.4 % were positive to anti-HDV-IgG.

CONCLUSION

Of the HBV carriers in Germany, 5-8 % reveal serologic evidence of coinfection with HDV. The vaccination against HBV is the key to prevent HDV infection; therefore, vaccination must strongly be propagated further on.

Hepatitis delta virus

Hepatitis delta virus (HDV) is a small, defective RNA virus that can infect only individuals who have hepatitis B virus (HBV); worldwide more than 15 million people are co-infected. There are eight reported genotypes of HDV with unexplained variations in their geographical distribution and pathogenicity. The hepatitis D virion is composed of a coat of HBV envelope proteins surrounding the nucleocapsid, which consists of a single-stranded, circular RNA genome complexed with delta antigen, the viral protein. HDV is clinically important because although it suppresses HBV replication, it causes severe liver disease with rapid progression to cirrhosis and hepatic decompensation. The range of clinical presentation is wide, varying from mild disease to fulminant liver failure. The prevalence of HDV is declining in some endemic areas but increasing in northern and central Europe because of immigration. Treatment of HDV is with pegylated interferon alfa; however, response rates are poor. Increased understanding of the molecular virology of HDV will identify novel therapeutic targets for this most severe form of chronic viral hepatitis.

Hepatitis D: thirty years after

The key to the discovery of the Hepatitis D Virus (HDV) was the description in Turin, Italy in the mid-1970s of the delta antigen and antibody in carriers of the hepatitis B surface antigen. The new antigen was first thought to be a marker of the Hepatitis B Virus (HBV) and in view of its intricate true nature, it would have possibly died away as another odd antigenic subtype of HBV, like many that were described in the 1970s. Fortunately, instead, a collaboration started in 1978 between the Turin group, and the National Institute of Health and Georgetown University in the US. With American facilities and expertise this collaboration led just a year later, in 1979, to the unfolding of an unexpected and amazing chapter in virology. Experiments in chimpanzees demonstrated that the delta antigen was not a component of the HBV but of a separate defective virus requiring HBV for its infection; it was named the hepatitis D virus to conform to the nomenclature of hepatitis viruses and classified within the genus Deltavirus. The animal experiments were also seminal in proposing to future clinical interpretation, the paradigm of a pathogenic infection (hepatitis D), that could develop only in HBV-infected patients, was mainly transmitted by superinfection of HDV on chronic HBV carriers and had the ability to strongly inhibit the helper HBV. The discovery of the HDV has driven three directions of further research: (1) The understanding of the replicative and infectious mechanisms of the HDV. (2) The assessment of its epidemiological and medical impact. (3) The search for a therapy for chronic hepatitis D (CHD). This review summarizes the progress achieved in each field of research in the thirty years that have passed since the discovery of HDV.

Hepatitis D: the comeback?

Hepatitis D virus (HDV) infection has considerably diminished in Europe since the 1970-1980s. The prevalence rates of chronic hepatitis D in HBsAg carriers in Italy have declined from 25% at the beginning of the 1980s to 8% in the 1990s. Similar declines in prevalence have been reported in Spain, Taiwan and Turkey. Better public health standards, HBV vaccination and the effect of measures to control the spread of human immunodeficiency virus have brought about a decline in the numbers of HBsAg carriers and therefore a decline in the HBV-dependent HDV. However, HDV has not declined further in Europe in the last decade, as the pool of fresh infections in migrants from HDV-endemic areas is counterbalancing the shrinking cohort of long-standing domestic infections acquired in the epidemic of the 1970-1980s. Hepatitis D remains an important health problem outside Europe, and new foci of infection continue to be identified in developing countries.

Seroprevalence of hepatitis delta virus infection among subjects with underlying hepatic diseases in Chennai, southern India

Four hundred million people are carriers of hepatitis B virus (HBV) worldwide and approximately 5% of these are reportedly positive for hepatitis delta virus (HDV). Several reports indicate a declining trend in the occurrence of HDV infection in the north of tropical India. To our knowledge, no study has been conducted to evaluate whether a similar epidemiological change is occurring in southern India. Therefore we evaluated the seroprevalence of HDV among 153 individuals with HBV-related liver diseases in Chennai, and assessed any change in epidemiological pattern by comparing the results with seroprevalence figures reported previously. Of the 153 patients screened, nine (5.9%) were reactive to anti-delta antibodies, six (3.9%) presented an evidence of past infection (IgG anti-delta positive) and three (2.0%) showed anti-HDV IgM, suggestive of recent HDV infection. Alanine transaminase elevation was not significant in HDV-associated infection compared with HBV alone-infected acute viral hepatitis (AVH) (P=0.82) and chronic liver disease (P=0.77) patients. The anti-HDV positivity in AVH was considerably low (6.6%), compared with previous Indian reports varying from 10.7% to >30%. HDV infection was relatively low and seems to play a minor determining factor of liver diseases in the tropical south Indian population.

Hepatitis B and hepatitis delta virus infection in South America

About 100,000 cases of acute hepatitis B virus (HBV) infection occur annually in South America. The overall prevalence of HBV infection in low risk populations ranges from 6.7% to 41%, while hepatitis B surface antigen (HBsAg) rates range from 0.4% to 13%. In high endemicity aboriginal or rural populations, perinatal transmission may play a major part in the spread of HBV. In urban populations, however, horizontal transmission, probably by sexual contact, is the predominant mode of spread, with higher rates of HBV positivity in lower socioeconomic groups. High risk populations such as health care workers and haemodialysis patients show higher rates of HBV infection than comparable populations elsewhere. The risk of posttransfusion hepatitis B remains high in some areas. Concomitant HBV infection may accelerate the chronic liver disease seen in decompensated hepatosplenic schistosomiasis. In the north, the prevalence of hepatitis delta virus (HDV) infection ranks among the highest in the world. In the south, the problem appears negligible although it is increasing within high risk urban communities. HDV superinfection has been the cause of large outbreaks of fulminant hepatitis. The cost of comprehensive or mass vaccination programmes remains unaffordable for most South American countries. Less expensive alternatives such as low dose intradermal schedules of immunisation have been used with success in selected adult subjects.

The French experience of treatment of chronic type D hepatitis with a 12-month course of interferon alpha-2B. Results of a randomized controlled trial

Hepatitis due to hepatitis delta virus (HDV) infection is generally associated with severe histological abnormalities and rapid progression of the disease. To assess the efficacy of recombinant interferon-a2b in treatment of chronic delta hepatitis, 22 patients were entered into a randomized controlled trial: 11 received interferon-a2b subcutaneously three times weekly for 12 months (5 MU/m2 for 4 months and then 3 MU/m2 for a further 8 months) and 11 were untreated. All patients were followed up for 6 months after the completion of therapy. Nine treated patients completed the trial: one was withdrawn with hyperthyroidism and one committed suicide. Serum ALT levels were normalized or significantly reduced, always within 3 months of initiating treatment, and remained so in 73% of treated patients at the 4th month and in 54.5% at the 12th month, compared with 18% and 18%, respectively, in the untreated group. Moreover, in seven of nine treated patients, interferon was associated with the clearance of serum HDV-RNA, associated with amelioration of the histological picture, whereas this occurred in only four of 11 untreated patients. On cessation of therapy, all patients but one experienced a biological and/or virological relapse over the 6-month follow up. In conclusion, our data confirm that HDV is sensitive to inhibition by interferon-a2b, although the schedule used did not achieve permanent control of the disease. The adverse effects of interferon require consideration; in particular, care will be needed to avoid serious psychiatric side effects.

Seroepidemiological prevalence of hepatitis delta virus in eastern Saudi Arabia

To describe hypercholesterolemia in an urban community in Saudi Arabia, total serum cholesterol (TSC) was measured in 966 apparently healthy males (475 Saudi Arabs, 351 other Arabs and 140 non-Arabs) using a portable analyzer (Boehringer Model[R]). Mean age was 35.9 years (SD+/-9.1) and mean body mass index (BMI) was 26.2 kg/m(2) (SD+/-3.4) with a mean TSC of 5.20 mmol (SD+/-1.21). Mean TSC was significantly higher among non-Arabs at 5.74 mmol/L (SD+/-1.48) than in Saudi Arabs at 4.93 mmol/L (SD+/-1.11), P<0.001 mmol/L. TSC was higher than 5.20 mmol/L in 44.3% and higher than 6.80 mmol/L in 6.9% of the population. TSC was higher than 6.80 mmol/L in 3.6% of Saudi Arabs, 8.0% in other Arabs and 15.7% in the non-Arabs. This calls for cholesterol screening of the indigenous male population for hypercholesterolemia and other coronary heart disease risk factors at every opportunity. Among expatriate males, a mass screening strategy might be appropriate. The health care system needs appropriate adjustment to deal with this growing health problem.

Prevalence of hepatitis virus infections in Albanian refugees

A sample of 393 Albanian refugees, including both children and adults, was tested for serological HAV, HBV, HDV and HCV markers. A high prevalence of infection with both the hepatitis A and B viruses was found, while HDV and HCV infections were uncommon. The overall prevalence of anti-HAV was 96%; it was very high in children 0-10 years, suggesting that HAV infection is largely acquired during childhood and that poor ambiental conditions influence the spreading of this viral infection. One or more serological markers of HBV infection were found in 295 Albanians (75%), confirming the endemic nature of this virus in the Albanian community. The overall prevalence of HBsAg was 19%, and the carrier rate was higher in males than in females. The high HBsAg prevalence among children suggests that HBV infection is usually acquired in early childhood. The serological data obtained in the Albanian sample examined clearly indicate the urgent need for measures to reduce the incidence of HAV and HBV infections and to avoid the further spread of HDV and HCV infections. Finally, the high prevalence of type B hepatitis indicates the necessity of vaccination against HBV for all risk groups and for all children at birth.

Delta hepatitis: molecular biology and clinical and epidemiological features

Hepatitis delta virus, discovered in 1977, requires the help of hepatitis B virus to replicate in hepatocytes and is an important cause of acute, fulminant, and chronic liver disease in many regions of the world. Because of the helper function of hepatitis delta virus, infection with it occurs either as a coinfection with hepatitis B or as a superinfection of a carrier of hepatitis B surface antigen. Although the mechanisms of transmission are similar to those of hepatitis B virus, the patterns of transmission of delta virus vary widely around the world. In regions of the world in which hepatitis delta virus infection is not endemic, the disease is confined to groups at high risk of acquiring hepatitis B infection and high-risk hepatitis B carriers. Because of the propensity of this viral infection to cause fulminant as well as chronic liver disease, continued incursion of hepatitis delta virus into areas of the world where persistent hepatitis B infection is endemic will have serious implications. Prevention depends on the widespread use of hepatitis B vaccine. This review focuses on the molecular biology and the clinical and epidemiologic features of this important viral infection.