Occult Hepatitis B virus infection in children

Introduction. Occult hepatitis B virus infection (OBI) holds significant clinical importance, representing a unique phase of viral infection where HBsAg-negative individuals exhibit reduced viral DNA replication. This DNA may be undetectable or present in serum but is consistently found in the liver. Materials and methods. A comprehensive review of the PubMed database, focusing on occult HBV infection in children from January 2013 to April 2023, was conducted. Results. Out of 914 identified articles, 111 publications met the criteria for “occult HBV infection in children.” During this phase, covalently closed circular DNA (cccDNA) exhibits low replication activity. The mechanisms underlying the suppression of HBV replication are associated with host immune responses and epigenetic factors. The prevalence of occult HBV infection in adults varies significantly across different geographic regions, influenced by risk factors for parenteral transmission and the sensitivity of assays used for detecting HBsAg and HBV DNA. Occult HBV infection in children is not well understood, with reported prevalence ranging from 20% to 54%. HBV transmission can occur parenterally, through blood transfusions, horizontal transmission, or liver transplantation, potentially leading to acute hepatitis. Reactivation can occur under immunosuppression, accelerating the progression from chronic hepatitis to cirrhosis, and contributing to the development of malignancies. Conclusions. Occult HBV infection in children is a form of chronic HBV infection with a variable prevalence. Testing for anti-HBc is crucial for diagnosing hepatitis of unknown etiology in children, as it can help detect chronic HBV infection.