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

Abstract

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.

Reactivation of Occult Hepatitis B Virus Infection During Long-Term Entecavir Antiviral Therapy

“…Occult hepatitis B virus (HBV) infection (OBI) is defined as surface antigen (HBsAg) seronegative, core antibody (HBcAb) seropositive, and HBV DNA positive in serum or liver ( de Almeida and de Paula, 2021 ). OBI may result in HBV reactivation (HBVr), acute exacerbations, cirrhosis, and hepatocellular carcinoma (HCC; Mak et al, 2020 ).…”

Low Risk of Occult Hepatitis B Infection among Vietnamese Blood Donors

“…Anti-HB-negative and anti-HBc-positive 19 (3) Anti-HB-positive and anti-HBc-negative 211 (34) Anti-HB-positive and anti-HBc-positive 223 (36) Anti-HB-negative and anti-HBc-negative 170 (27) We found by nested PCR that HBV DNA was present in two samples (0.3%; in OP038923 and OP038924). The OBI positive blood donors were 31 and 30 years old (Figure 2).…”

“…To eliminate the spread of HBV through vertical or horizontal transmission, the diagnosis of OBI among blood donors is of importance. In general, OBI prevalence varies considerably by regions, genotypes, molecular methods used, detection limits of HBsAg tests, and risk groups [8,11,27]. In Laos, a prevalence of 10.9% was reported among HBsAg-negative blood donors [28], while a study from China found a low OBI prevalence of 0.013% only [29].…”

Molecular characteristics of the full-length genome of occult hepatitis B virus from blood donors in China

“…In conclusion, OBI maintained by host, viral, immunological, and/or epigenetic factors, is one of the most challenging clinical features in the viral hepatitis study 50 . We conducted a comprehensive survey about the characteristics of a large sample size of the full-length genome of OBI.…”

“…OBI is the potential risk of HBV transmission through blood transfusion (the minimal infectious dose is 3 IU/ml), organ transplantation, and from occult infected mothers to newborns 9 – 11 , and episodes of reactivation can occur after the development of an immunodeficiency, and then acute hepatitis and occasionally fulminant hepatitis may happen after reactivation 49 . The reactivation can make the progression of liver damage, resulting in fibrotic conditions that promote the development of cirrhosis 50 . The study of characteristics of a large sample size of the full-length genome of OBI may better to understand the situation of OBI infections in blood donors and further help us to pay attention to the fact that reactivation of OBI strains occurs.…”