Occult Hepatitis C Virus Infection: A Review

Occult hepatitis C virus (HCV) infection (OCI), first described in 2004, is defined as the presence of HCV RNA in hepatocytes or peripheral blood mononuclear cells without detectable HCV RNA in the serum. Here, we aimed to review the epidemiology, diagnostic methods, clinical implications and potential management recommendations currently described in the literature, as well as the future directions for investigation of this entity. PubMed and Cochrane databases were searched with combination of the following keywords: "occult", "hepatitis C virus", and "occult HCV infection". There are data to support OCI as a potential culprit in cryptogenic liver disease. There are also consistent data demonstrating the existence of OCI in specific populations, such as dialysis, human immunodeficiency virus-infected and hepatitis B virus-infected patients, and also in the general population. While the gold standard for diagnosis is liver biopsy, examination of peripheral blood mononuclear cells may be a reliable, safer alternative method of diagnosis. Occult HCV infection is likely associated with liver fibrosis and progression of liver disease. Additional studies are required to determine the infectivity of OCI patients, as well as clarify the natural course and specific clinical implications of OCI. Lastly, studies are needed to determine whether treatment of OCI leads to decreased morbidity and/or mortality.