Sexual Dimorphism in Chronic Hepatitis B Virus (HBV) Infection: Evidence to Inform Elimination Efforts

Distinct virologic trajectories in chronic hepatitis B identify heterogeneity in response to nucleos(t)ide analogue therapy

Background & Aims

The dynamics of HBV viral load (VL) in patients with chronic hepatitis B (CHB) on nucleos(t)ide analogue (NA) treatment and its relationship with liver disease are poorly understood. We aimed to study longitudinal VL patterns and their associations with CHB clinical outcomes.

Methods

Utilising large scale, routinely collected electronic health records from six centres in England, collated by the National Institute for Health and Care Research Health Informatics Collaborative (NIHR HIC), we applied latent class mixed models to investigate VL trajectory patterns in adults receiving NA treatment. We assessed associations of VL trajectory with alanine transaminase, and with liver fibrosis/cirrhosis.

Results

We retrieved data from 1,885 adults on NA treatment (median follow-up 6.2 years, IQR 3.7-9.3 years), with 21,691 VL measurements (median 10 per patient, IQR 5-17). Five VL classes were identified from the derivation cohort (n = 1,367, discrimination: 0.93, entropy: 0.90): class 1 'long term suppression' (n = 827, 60.5%), class 2 'timely virological suppression' (n = 254, 18.6%), class 3 'persistent moderate viraemia' (n = 140, 10.2%), class 4 'persistent high-level viraemia' (n = 44, 3.2%), and class 5 'slow virological suppression' (n = 102, 7.5%). The model demonstrated a discrimination of 0.93 and entropy of 0.88 for the validation cohort (n = 518). Alanine transaminase decreased variably over time in VL-suppressed groups (classes 1, 2, 5; all p <0.001), but did not significantly improve in those with persistent viraemia (classes 3, 4). Patients in class 5 had twofold increased hazards of fibrosis/cirrhosis compared with class 1 (adjusted hazard ratio, 2.00; 95% CI, 1.33-3.02).

Conclusions

Heterogeneity exists in virological response to NA therapy in CHB patients, with over 20% showing potentially suboptimal responses. Slow virological suppression is associated with liver disease progression.

Impact and implications

Treatment recommendations for people living with chronic hepatitis B virus (HBV) infection are becoming less stringent, meaning that more of the population will be eligible to receive therapy with nucleos(t)ide analogue agents. We explored outcomes of HBV treatment in a large UK dataset, describing different responses to treatment, and showing that the viral load is not completely suppressed after 1 year in about one in five cases, associated with an increased risk of liver complications. As treatment is rolled out more widely, patients and clinicians need to be aware of the potential for incomplete virologic responses. The findings can support the identification of high-risk individuals, improve early fibrosis and cirrhosis prediction, guide monitoring and preventive interventions, and support public health elimination goals.

Hepatitis B Virus-Related Cirrhosis and Hepatocellular Carcinoma Hospital Discharge Rates from 2005 to 2021 in Spain: Impact of Universal Vaccination

Background: The main consequences of chronic hepatitis B virus (HBV) infections are cirrhosis and hepatocellular carcinoma (HCC), both associated with frequent hospitalization. The aim of this study was to analyze the impact of universal HBV vaccination in Spain on chronic HBV-related hospital discharges from 2005 to 2021. Methods: Using data from the Minimum Basic Data Set of the Spanish National Health System, we calculated the hospital discharge rate ratio (HDRR) and 95% confidence interval (CI) values for chronic HBV-related discharges between 2005 and 2021. For comparative purposes, we calculated the HDRR and 95% confidence interval (CI) values for the early (2005-2013) and later (2014-2021) periods and the vaccinated compared with unvaccinated cohorts for the 20-39 age group. Results: The hospital discharge rate per 1,000,000 people was 3.08 in 2005 and 4.50 in 2021 for HCC, and 4.81 in 2005 and 1.92 in 2021 for cirrhosis. Comparing the early and later periods, values were higher for HCC (HDRR 1.13; 95% CI: 1.06-1.20) and lower for cirrhosis (HDRR 0.56; 95% CI: 0.51-0.60). The rate for the 20-39 age group was lower for the vaccinated compared with the unvaccinated cohorts overall (HDRR 0.53; 95% CI: 0.45-0.62), for HCC (HDRR 0.66; 95% CI: 0.53-0.82), and for cirrhosis (HDRR 0.41; 95% CI: 0.33-0.53). Conclusions: This study describes the important impact, after 25 years, of universal HBV vaccination in Spain: cirrhosis hospital discharge rate was reduced, and the vaccinated cohorts, compared with the unvaccinated cohorts in the 20-39 age group, had a lower hospital discharge rate of both HCC and cirrhosis.

Self-reported hepatitis B testing among noninstitutionalized adults in the United States before the implementation of universal screening, 2013-2017: A nationwide population-based study

In 2023, the US Centers for Disease Control and Prevention recommended universal screening for hepatitis B virus (HBV); however, the proportion of US adults screened before implementing this recommendation is unknown. We analysed nationally representative data from the National Health Interview Survey (2013-2017) on self-reported HBV testing among noninstitutionalized US adults ≥18 years. We employed Poisson logistic regression to identify factors associated with self-reported testing, using a conceptual framework that included four overarching factors: sociodemographic characteristics, healthcare access, health-seeking behaviours and experiences, and access to internet-based health information. Among 149,628 survey respondents, the self-reported HBV testing rate was 27.2% (95% CI 26.2-28.7) and increased by 1.7% from 2013 to 2017 (p = .006). In adjusted analysis, health-seeking behaviours and experiences had the strongest associations of self-reported testing including a history of hepatitis (AOR 2.68, 95% CI 1.92-3.73), receipt of hepatitis B vaccination (AOR 5.11, 95% CI 4.61-5.68) and prior testing for hepatitis C (AOR 9.14, 95% CI 7.97-10.48) and HIV (AOR 2.69, 95% CI 2.44-2.97). Other factors associated with testing included being male (AOR 1.14, 95% CI 1.03-1.26), ages 30-44 years (AOR 1.37, 95% CI 1.17-1.61), 45-60 years (AOR 1.55, 95% CI 1.30-1.80) and ≥60 years (AOR 1.53, 95% CI 1.28-1.84), residence in the Western US region (AOR 1.23, 95% CI 1.06-1.43), and access to internet-based health information (AOR 1.32, 95% CI 1.18-1.47). Being Hispanic was associated with lower odds of testing (AOR 0.80, 95% CI 0.66-0.97). These findings may help guide optimal HBV screening in the universal testing era.

CRISPR-Cas based genome editing for eradication of human viruses

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system possess a broad range of applications for genetic modification, diagnosis and treatment of infectious as well as non-infectious disease. The CRISPR-Cas system is found in bacteria and archaea that possess the Cas protein and guide RNA (gRNA). Cas9 and gRNA forms a complex to target and cleave the desired gene, providing defense against viral infections. Human immunodeficiency virus (HIV), hepatitis B virus (HBV), herpesviruses, human papillomavirus (HPV), and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cause major life threatening diseases which cannot cure completely by drugs. This chapter describes the present strategy of CRISPR-Cas systems for altering the genomes of viruses, mostly human ones, in order to control infections.

Prevalence of Non-Alcoholic Fatty Liver Disease and Its Impact on Fibrosis Risk in Inactive Chronic Hepatitis B Patients: Insights from a Cross-Sectional Study

Background: Chronic hepatitis B (CHB) and non-alcoholic fatty liver disease (NAFLD) are significant causes of chronic liver disease, potentially leading to liver cirrhosis and hepatocellular carcinoma. Moreover, the coexistence of CHB and NAFLD is increasingly common, although the relationship between NAFLD and inactive CHB infection remains poorly understood. Objectives: This study aimed to investigate the prevalence of NAFLD among patients with inactive CHB, identify risk factors for NAFLD, and determine predictors of significant fibrosis in these patients. Methods: This single-center cross-sectional study targeted patients with inactive CHB at Sultan Qaboos University Hospital from January 2010 to November 2021. Results: A total of 425 patients with inactive CHB were identified, of which 53.1% were male and 62.6% were aged 40-60 years. The prevalence of NAFLD was 47.8%. Various independent factors were associated with NAFLD, including type 2 diabetes mellitus, elevated low-density lipoprotein levels, high hemoglobin levels, low platelet counts, and normal alpha-fetoprotein levels. Significant associations were noted between NAFLD and significant fibrosis, with 10.5% of CHB patients with NAFLD exhibiting significant fibrosis compared to 1.4% of those without NAFLD. Other significant parameters included male gender, increased age, high alanine transaminase levels, elevated hemoglobin, and decreased platelet levels. Conclusions: The high prevalence of NAFLD in patients with inactive CHB and its associations with increased fibrosis and cirrhosis risk underscore the need for comprehensive management strategies for these patients.

Differences between males and females in infectious diseases notifications in the EU/EEA, 2012 to 2021

BackgroundThere are differences between males and females for most diseases both for exposure and course of illness, including outcome. These differences can be related to biological sex or gender i.e. socio-cultural factors that may impact exposure and healthcare access.AimWe aimed to quantify differences between males and females in infectious disease notifications in Europe and identify countries with these differences significantly different from the European Union and European Economic Area (EU/EEA) average.MethodsNotifiable infectious disease surveillance data are reported by EU/EEA countries to ECDC. We retrieved surveillance data for 2012-2021. Using a cut-off median of annual disability-adjusted life years above 1 per 100,000 population, we included 16 infectious diseases. We calculated median male proportion and interquartile range by disease, year, country and age group and used boxplots to identify outliers.ResultsFor campylobacteriosis, acute hepatitis B, Legionnaires' disease, malaria and HIV and AIDS, all countries had male proportion above 50%. Most countries had a male proportion below 50% for pertussis (25/28 countries), STEC infection (21/28 countries) and Chlamydia trachomatis infection (16/24 countries). Chlamydia trachomatis infection and listeriosis showed the greatest dispersion of male proportion across age groups. Most outliers were countries reporting few cases.ConclusionWe observed important differences in male proportion across infectious disease notifications in EU/EEA countries. For some diseases with high male proportions in all countries, such as HIV and hepatitis B, behaviours play a role in disease transmission. Screening offered to specific populations may explain differences across countries for example for C. trachomatis infection.

Sex and ethnic disparities in hepatitis B evaluation and treatment across the world

BACKGROUND & AIMS

Oral antiviral therapy with nucleos(t)ide analogues (NAs) for chronic hepatitis B (CHB) is well-tolerated and lifesaving, but real-world data on utilization are limited. We examined rates of evaluation and treatment in patients from the REAL-B consortium.

METHODS

This was a cross-sectional study nested within our retrospective multinational clinical consortium (2000-2021). We determined the proportions of patients receiving adequate evaluation, meeting AASLD treatment criteria, and initiating treatment at any time during the study period. We also identified factors associated with receiving adequate evaluation and treatment using multivariable logistic regression analyses.

RESULTS

We analyzed 12,566 adult treatment-naïve patients with CHB from 25 centers in 9 countries (mean age 47.1 years, 41.7% female, 96.1% Asian, 49.6% Western region, 8.7% cirrhosis). Overall, 73.3% (9,206 patients) received adequate evaluation. Among the adequately evaluated, 32.6% (3,001 patients) were treatment eligible by AASLD criteria, 83.3% (2,500 patients) of whom were initiated on NAs, with consistent findings in analyses using EASL criteria. On multivariable logistic regression adjusting for age, sex, cirrhosis, and ethnicity plus region, female sex was associated with adequate evaluation (adjusted odds ratio [aOR] 1.13, p = 0.004), but female treatment-eligible patients were about 50% less likely to initiate NAs (aOR 0.54, p <0.001). Additionally, the lowest evaluation and treatment rates were among Asian patients from the West, but no difference was observed between non-Asian patients and Asian patients from the East. Asian patients from the West (vs. East) were about 40-50% less likely to undergo adequate evaluation (aOR 0.60) and initiate NAs (aOR 0.54) (both p <0.001).

CONCLUSIONS

Evaluation and treatment rates were suboptimal for patients with CHB in both the East and West, with significant sex and ethnic disparities. Improved linkage to care with linguistically competent and culturally sensitive approaches is needed.

IMPACT AND IMPLICATIONS

Significant sex and ethnic disparities exist in hepatitis B evaluation and treatment, with female treatment-eligible patients about 50% less likely to receive antiviral treatment and Asian patients from Western regions also about 50% less likely to receive adequate evaluation or treatment compared to Asians from the East (there was no significant difference between Asian patients from the East and non-Asian patients). Improved linkage to care with linguistically competent and culturally sensitive approaches is needed.

Hepatitis B Virus Prevalence among HIV-Uninfected People Living in Rural and Peri-Urban Areas in Botswana

(1) Background: we determined the prevalence of the hepatitis B virus (HBV) amongst people without human immunodeficiency virus (HIV) in rural and peri-urban areas in Botswana. (2) Methods: We screened for the hepatitis B surface antigen (HBsAg) from archived plasma samples of people without HIV (n = 2135) randomly selected from the Botswana Combination Prevention Program (BCPP) (2013-2018). We sequenced 415 bp of the surface region using BigDye sequencing chemistry. (3) Results: The median age of participants was 31 (IQR: 24-46) and 64% (1360/2135) were female. HBV prevalence was 4.0% (86/2135) [95% CI: 3.3-4.9]) and ranged between 0-9.2%. Older participants (>35 years) had increased odds of HBV positivity (OR: 1.94; 95% CI: [1.32-2.86]; p = 0.001). Thirteen samples were sequenced and seven (53.8%) were genotype A, three (23.1%) were genotype D and genotype E each. Clinically significant mutations were identified in the surface region, but no classic drug resistance mutations were identified. (4) Conclusions: We report an HBV prevalence of 4.0% (95% CI 3.3-4.9) among people without HIV in rural and peri-urban communities in Botswana with varying rates in different communities. A comprehensive national HBV program is required in Botswana to guide HBV prevention, testing and management.

Persistence and risk factors of occult hepatitis B virus infections among antiretroviral therapy-naïve people living with HIV in Botswana

Aim

This study aimed to determine the kinetics of occult hepatitis B virus infections (OBI) among people with HIV (PWH).

Methods

The study used archived plasma samples from longitudinal HIV natural history studies. We identified new OBI cases and assessed risk factors for OBI using Cox proportional hazards regression analysis.

Results

At baseline, 8 of 382 [(2.1%) (95% CI: 1.06-4.1)] samples tested positive for hepatitis B surface antigen (HBsAg+). Of the 374 HBsAg-negative samples, 76 had sufficient sample volume for HBV DNA screening. OBI positivity (OBI+) at baseline was reported in 11 of 76 [14.7 95% CI (8.3-24.1)] HBsAg-negative (HBsAg-) participants. Baseline HBsAg-negative samples with sufficient follow-up samples (n = 90) were used for analysis of newly identified OBI cases. Participants contributed 129.74 person-years to the study and were followed for a median of 1.02 years (IQR: 1.00-2.00). Cumulatively, there were 34 newly identified OBI cases from the 90 participants, at the rate of 26.2/100 person-years (95% CI: 18.7-36.7). Newly identified OBI cases were more common among men than women (61.1% vs. 31.9%) and among participants with CD4+ T-cell counts ≤450 cells/mL (p-value = 0.02). Most of the newly identified OBI cases [55.9% (19/34)] were possible reactivations as they were previously HBV core antibody positive.

Conclusion

There was a high rate of newly identified OBI among young PWH in Botswana, especially in men and in participants with lower CD4+ T-cell counts. OBI screening in PWH should be considered because of the risk of transmission, possible reactivation, and risk factors for the development of chronic liver disease, including hepatocellular carcinoma.

Hepatitis B in Pediatric Population: Observational Retrospective Study in Romania

Hepatitis B virus (HBV) is a frequent cause of chronic hepatitis worldwide, with an estimated 5.6 million children under 5 years being infected. In Romania, there are no available epidemiology reports on large cohorts in children. We aimed to assess the profile of pediatric chronic HBV infection in southern Romania. We conducted an observational retrospective study on 506 HBV-infected children. Based on alaninaminotransferase (ALT), HBV serology and viremia, we identified four states of the disease. We correlated age, gender, household HBV infection, coinfection with other viruses and laboratory parameters. Most patients were in a positive HBV envelope antigen (HBeAg) immune-active state (65.4%). Age at diagnosis was significantly lower for those with household infection (p < 0.05). ALT values were not significantly different between positive or negative HBeAg patients in the immune-active state (p = 0.780). ALT values were higher in patients with hepatitis D virus (HDV)-associated infection (p < 0.001). Children with a household HBV infection had a high viraemia more frequently when compared to those with no infected relative (79.3% vs. 67.4%) (p < 0.001), but the ALT values were not significantly different (p = 0.21). Most of the patients are in an immune-active state (high ALT, high viremia). The percentages of HBV- and HDV-associated infections are high, but lower than the reported prevalence in Romania in the general population.

Evaluating the hepatitis B vaccination impact in the Republic of Moldova: A nationwide representative serosurvey of children born in 2013

Objectives

The WHO European Region set targets for the control of hepatitis B through immunization, including prevalence of hepatitis B surface antigen (HBsAg) at ≤0.5% in vaccinated cohorts. The Republic of Moldova implemented universal hepatitis B vaccination since 1995. We conducted a nationwide representative serosurvey to estimate HBsAg seroprevalence in children born in 2013 to validate hepatitis B control targets.

Methods

We used probability-based sampling and a two-stage cluster design. All children born in 2013 and registered in primary healthcare facilities were eligible for participation. We tested blood samples of all participants for hepatitis B core antibody (anti-HBc), using Enzyme-Linked Immunosorbent Assay (ELISA). Anti-HBc-positive samples were tested for HBsAg and HBsAg-positive samples confirmed, using ELISA. We obtained information on hepatitis B vaccination from vaccination cards.

Results

Of 3352 sampled children, 3064 (91%) participated. Most participating children were 7 years old (n = 3030, 99%), 1426 (48%) were girls. The weighted, national seroprevalence estimate was 3.1% (95% confidence interval = 2.1-4.5) for anti-HBc and 0.21% (95% confidence interval = 0.08-0.53) for HBsAg.

Conclusion

The study demonstrated the impact of hepatitis B vaccination and allowed the Republic of Moldova to validate regional hepatitis B control targets. Other countries with high vaccination coverage could use hepatitis B serosurveys and apply for validation. Sustained efforts in the Republic of Moldova will be crucial on the path to hepatitis B elimination.

Prevalence of hepatitis B virus infection among general population of Armenia in 2021 and factors associated with it: a cross-sectional study

OBJECTIVES

This study sought to determine the prevalence and associated factors of hepatitis B virus (HBV) infection ever in life and chronic HBV infection in Armenia.

DESIGN

A population-based cross-sectional seroprevalence study combined with a phone survey of tested individuals.

SETTING

All administrative units of Armenia including 10 provinces and capital city Yerevan.

PARTICIPANTS

The study frame was the general adult population of Armenia aged ≥18 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

The participants were tested for anti-HBV core antibodies (anti-HBc) and HBV surface antigen (HBsAg) using third-generation enzyme immunoassays. In case of HBsAg positivity, HBV DNA and hepatitis D virus (HDV) RNA PCR tests were performed. Risk factors of HBV infection ever in life (anti-HBc positivity) and chronic HBV infection (HBsAg positivity) were identified through fitting logistic regression models.

RESULTS

The seroprevalence study included 3838 individuals 18 years and older. Of them, 90.7% (3476 individuals) responded to the phone survey. The prevalence of anti-HBc positivity was 14.1% (95% CI 13.1% to 15.2%) and HBsAg positivity 0.8% (95% CI 0.5% to 1.1%). The viral load was over 10 000 IU/mL for 7.9% of HBsAg-positive individuals. None of the participants was positive for HDV. Risk factors for HBsAg positivity included less than secondary education (aOR=6.44; 95% CI 2.2 to 19.1), current smoking (aOR=2.56; 95% CI 1.2 to 5.6), and chronic liver disease (aOR=8.44; 95% CI 3.0 to 23.7). In addition to these, risk factors for anti-HBc positivity included age (aOR=1.04; 95% CI 1.04 to 1.05), imprisonment ever in life (aOR=2.53; 95% CI 1.41 to 4.56), and poor knowledge on infectious diseases (aOR=1.32; 95% CI 1.05 to 1.67), while living in Yerevan (vs provinces) was protective (aOR=0.74; 95% CI 0.59 to 0.93).

CONCLUSION

This study provided robust estimates of HBV markers among general population of Armenia. Its findings delineated the need to revise HBV testing and treatment strategies considering higher risk population groups, and improve population knowledge on HBV prevention.

Identification of Adolescent Menarche Status Using Biplanar X-ray Images: A Deep Learning-Based Method

The purpose of this study is to develop an automated method for identifying the menarche status of adolescents based on EOS radiographs. We designed a deep-learning-based algorithm that contains a region of interest detection network and a classification network. The algorithm was trained and tested on a retrospective dataset of 738 adolescent EOS cases using a five-fold cross-validation strategy and was subsequently tested on a clinical validation set of 259 adolescent EOS cases. On the clinical validation set, our algorithm achieved accuracy of 0.942, macro precision of 0.933, macro recall of 0.938, and a macro F1-score of 0.935. The algorithm showed almost perfect performance in distinguishing between males and females, with the main classification errors found in females aged 12 to 14 years. Specifically for females, the algorithm had accuracy of 0.910, sensitivity of 0.943, and specificity of 0.855 in estimating menarche status, with an area under the curve of 0.959. The kappa value of the algorithm, in comparison to the actual situation, was 0.806, indicating strong agreement between the algorithm and the real-world scenario. This method can efficiently analyze EOS radiographs and identify the menarche status of adolescents. It is expected to become a routine clinical tool and provide references for doctors' decisions under specific clinical conditions.

An Intersectional Approach to Hepatitis B

Hepatitis B is a chronic condition, primarily associated with hepatitis B viral infection in early life. The failure of prevention and appropriate management can lead to subsequent liver cirrhosis and cancer. Hepatitis B most commonly affects people born in Asia and Sub-Saharan Africa and their global diasporas. The physical, psychological, and social impacts of hepatitis B are strongly influenced by sex and gender. Inequities in access to timely, sensitive diagnosis and effective management arise from interactions between structural inequalities related to race, ethnicity, Indigenous/settler status, class, and geography. The biomedical response to hepatitis B has led to advances in prevention, diagnosis, and treatment, but many affected communities have explanatory health belief models that differ from that of biomedicine. We argue that an intersectional approach, led by affected people and communities, can integrate biomedicine with the lived experience and social context that give purpose to and shape all personal, communal, clinical, and public health responses to hepatitis B. This approach has the potential to enable a consciously equitable, effective response to the biopsychosocial complexities of hepatitis B, improve the health and wellbeing of people living with hepatitis B, and reduce hepatitis B-associated mortality.

High Prevalence of Hepatitis B Virus Infection Among People With HIV in Rural and Periurban Communities in Botswana

Background

We aimed to determine the prevalence of hepatitis B virus (HBV) infection among people with human immunodeficiency virus (PWH) in rural and periurban communities in Botswana.

Methods

PWH from a previous population-based study, the Botswana Prevention Combination Project, which enrolled adults in 30 communities across Botswana (2013-2018), were screened for HBV surface antigen (HBsAg) and HBV core antibody (anti-HBc). HBsAg-positive (HBsAg+) samples were further screened for HBV core immunoglobulin M antibodies (anti-HBc immunoglobulin M [IgM]) and HBV e antigen (HBeAg). We quantified HBV viral load on participants who tested positive (n = 148) and negative for HBsAg (n = 381).

Results

Of 3304 participants tested, 271 (8% [95% confidence interval {CI}, 7%-9%]) were HBsAg+ while 1788 (56% [95% CI, 54%-57%]) of 3218 PWH whom we tested had positive anti-HBc. Approximately 88% of HBsAg+ participants were on antiretroviral therapy (ART), 40% and 56% of whom were receiving lamivudine- and tenofovir-containing ART, respectively. Male sex (relative risk ratio [RRR], 1.8 [95% CI, 1.2-2.7]) and the northern geographic region (RRR, 2.5 [95% CI, 1.4-4.7]) were independent predictors of HBV infection (HBsAg+). Of 381 persons with negative HBsAg who were tested for occult HBV, 126 (33% [95% CI, 29%-38%]) had positive HBV DNA. Eleven participants were highly viremic with high HBV viral load while on a lamivudine- or tenofovir-containing regimen. Ten (91%) of these participants also had positive HBeAg serology, while 4 (36%) had positive anti-HBc IgM serology.

Conclusions

The prevalence of HBV was high among PWH in Botswana while on ART regimens with activity against HBV.

Many Ways to Communicate-Crosstalk between the HBV-Infected Cell and Its Environment

Chronic infection with the hepatitis B virus (HBV) affects an estimated 257 million people worldwide and can lead to liver diseases such as cirrhosis and liver cancer. Viral replication is generally considered not to be cytopathic, and although some HBV proteins may have direct carcinogenic effects, the majority of HBV infection-related disease is related to chronic inflammation resulting from disrupted antiviral responses and aberrant innate immune reactions. Like all cells, healthy and HBV-infected cells communicate with each other, as well as with other cell types, such as innate and adaptive immune cells. They do so by both interacting directly and by secreting factors into their environment. Such factors may be small molecules, such as metabolites, single viral proteins or host proteins, but can also be more complex, such as virions, protein complexes, and extracellular vesicles. The latter are small, membrane-enclosed vesicles that are exchanged between cells, and have recently gained a lot of attention for their potential to mediate complex communication and their potential for therapeutic repurposing. Here, we review how HBV infection affects the communication between HBV-infected cells and cells in their environment. We discuss the impact of these interactions on viral persistence in chronic infection, as well as their relation to HBV infection-related pathology.