Hepatitis C virus chronicity and oncogenic potential: Vaccine development progress

Hepatitis C virus (HCV) infection is a major health problem worldwide. It can cause liver cirrhosis and hepatocellular carcinoma (HCC), making it a cause of morbidity from liver disease. Thus, there is an urgent need for a prophylactic HCV vaccine. Fortunately, modern medicine has transformed the therapy for HCV infection through development of direct-acting antiviral agents (DAAs), achieving high rates of sustained virologic response and giving significant relief from HCC and associated mortality, but unfortunately it fails to eradicate the risk of HCC, especially in HCV-cleared patients with already advanced liver disease. Additionally, DAA-cured patients do not develop sufficient antiviral immunity and are susceptible to reinfection. A comprehensive strategy to control HCV infection must include a vaccine development approach in which the host can develop humoral and cellular immunity to eradicate HCV successfully; however, this remains a challenge as HCV has developed systems to evade immune attacks from its host. This review highlights the current understanding of HCV's effect on liver disease and cancer progression, the nature of immune responses from cell populations interacting with HCV, and the current strategies for vaccine development. The information in this review will advance prophylactic intervention strategies for HCV infection, with the end goal being to prevent chronicity and subsequent liver disease leading to HCC.