High rate of occult hepatitis B virus infection in hemodialysis units of KwaZulu-Natal, South Africa

Prevalence of occult hepatitis B infection among treatment-naive persons living with HIV in Ghana

Hepatitis B virus (HBV) constitutes a significant global health challenge, with more than 2 billion people infected globally and almost 291 million chronic cases. In Africa, coinfection of HBV with Human Immunodeficiency Virus (HIV) is high, yet the condition remains overlooked in many countries. While antiretroviral therapy (ART) has improved HIV survival, viral hepatitis continues to contribute to morbidity and mortality. Occult Hepatitis B infection (OBI), characterized by a low-level of HBV DNA in individuals with negative hepatitis B surface antigen (HBsAg), is an emerging concern among HIV seropositive individuals due to the risk of HBV reactivation and associated complications, especially hepatocellular carcinoma (HCC). Ghana has an estimated HBV/HIV coinfection prevalence of 13.6% making it important to also determine potential cases of OBI. This study aims to assess OBI prevalence in persons living with HIV (PLHIV). A cross-sectional study was conducted in five health facilities in the Cape Coast Metropolis. HBV-related serological markers were determined among 116 PLHIV using the Enzyme-Linked Immunosorbent Assay (ELISA) method. HBV DNA was extracted from 30 participants found to be HBsAg negative but positive for hepatitis B core antibody (HBcAb+). Nested PCR was employed in detecting HBV DNA and HBV viral load was performed using qPCR. The median age of the participants was 37 years (IQR 22-65). Serologically, 7.8% (n = 9, 95% CI: 3.5-22.7), 12.1% (n = 14), and 25.9% (n = 30) tested positive for solely HBsAg, HBsAb, and HBcAb respectively. OBI prevalence among HBsAg-/HBcAb+ participants was 16.7% (n = 5, 95% CI: 6.5-23.7) with a median HBV DNA level of 139.2 IU/ml (IQR, 96.7-142.0). The prevalence of OBI among HIV-positive participants in the Cape Coast Metropolis highlights the need to consider screening for HBV among HIV patients using nucleic acid amplification tests. This can inform medical management and reduce the risk of liver complications, including HCC.

Prevalence of occult hepatitis B virus infection in Egypt: a systematic review with meta-analysis

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is a major public health problem. The clinical importance of OBI stems from the fact that it can be transmitted to healthy individuals at extremely low viral load levels. Additionally, immunosuppression has the potential to trigger viral replication, which can result in life-threatening liver decompensation. Despite several studies examining the prevalence of OBI, the pooled prevalence of OBI in Egypt remains unknown, particularly among blood donors and high-risk individuals, to whom intervention should be targeted.

METHODS

A comprehensive literature search of the following databases was conducted from inception to October 2022 using the following keywords: occult hepatitis B virus infection or occult HBV infection or OBI and Egypt in MEDLINE [PubMed], Scopus, Google Scholar, and Web of Science. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. I-squared and Cochran's Q were used to measure the heterogeneity between the studies, and based on the random effects model, results were reported as proportions (%) with a 95% confidence interval (CI). Analyses of subgroup analyses were conducted based on the target population. Sensitivity analyses were conducted using the leave-one-out approach to test the robustness of the results.

RESULTS

A total of 50 studies with 62 estimations of OBI were included, 19 in patients who were HBsAg-negative and anti-HBc-positive and 43 in patients who were HBsAg-negative. The highest prevalence (41%) was among multi-transfused patients according to  studies that report occult hepatitis B virus prevalence in an HBsAg-negative population, while the pooled prevalence of OBI among patients on hemodialysis, patients with chronic hepatitis C infection, patients with hepatocellular carcinoma (HCC), and patients with liver cirrhosis was 17%, 10%, 24%, and 13%, respectively. On the other hand, among studies that report OBI prevalence in HBsAg-negative and anti-HBc-positive individuals, the pooled prevalence of OBI among blood donors, patients with chronic hepatitis C infection, and patients with HCC was 12%, 15%, and 31%, respectively. Also, the majority of studies examining the genetic background of OBI have found that genotype D is the most prevalent.

CONCLUSION

 This study highlights the high prevalence in OBI among blood donors and high-risk populations in Egypt. The implementation of HBV nucleic acid amplification testing (NAT) may increase the safety of blood transfusions by excluding all HBV DNA-positive donations. However, the cost-effectiveness of these tests should be investigated.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

Molecular and serological characterization of occult hepatitis B among blood donors in Maputo, Mozambique

BACKGROUND

Occult hepatitis B virus (HBV) - characterized by the absence of detectable HBsAg in the presence of HBV DNA - represents a potential threat for blood safety.

OBJECTIVES

This study was conducted with the aim to investigate the serological and molecular characterization of occult HBV infection (OBI) among blood donors in Mozambique.

METHODS

1,502 blood donors were tested for HBsAg. All HBsAg-negative individuals were tested for HBV DNA. Antibodies against HBV core, surface and HBe antigen (anti-HBc, anti-HBs, HBeAg) were measured in HBV DNA positive individuals.

FINDINGS

1435 serum samples were HBsAg negative and 16 positive for HBV DNA, 14 confirmed to have OBI, corresponding to a frequency of 0.98%. Of the 14 OBI infections identified, 13/14 (92.8%) were positive for anti-HBc, 4/14 (28.5%) for anti-HBs, and no samples were reactive for HBeAg. Of the 14 OBI cases, nine samples (64.2%) were sequenced for the S/P region. Eight samples (88.9%) belonged to genotype A1 and one (11.1%) to genotype E. One escape mutation (T123A) associated with OBI and various amino acid substitutions for genotype A1 and E were observed.

MAIN CONCLUSIONS

Our results show the importance of using nucleic acid amplification test to detect occult hepatitis B infection in blood donors in Mozambique.