Hepatitis C: epidemiology, diagnosis, natural history and therapy.

With an estimated prevalence of 3% in the world population (around 170 million infected individuals worldwide), hepatitis C virus (HCV) heavily burdens public health. Even though the incidence of new infections is declining, at least in industrialized countries where they are mainly restricted to intravenous drug users, morbidity and mortality (which means also HCV-induced costs) associated with HCV infection are expected to increase over the next decade. Models suggest that the incidence of hepatocellular carcinoma and HCV-related mortality will still increase until about 2015. The prevalence of the disease, the risk of progression of fibrosis to cirrhosis or hepatocellular carcinoma, mainly but not only in patients with liver comorbidities such as metabolic syndrome and/or heavy alcohol intake, evidences: (1) the need for a screening of chronic HCV infection as defined by both anti-HCV antibodies and detectable HCV RNA, (2) the evaluation of the extrahepatic (cryoglobulinemia-related vasculitis) or liver impact of chronic infection (by liver biopsy or noninvasive markers of fibrosis) and (3) the discussion of an antiviral treatment which is mainly the combination of pegylated interferon (one weekly subcutaneous injection) and ribavirin, a nucleosidic analogue with a twice daily oral intake. This 'standard of care' results in a mean of 60% of sustained virologic response corresponding to viral eradication, which allows the inactivation of necroinflammation and the remodeling of fibrosis. New antiviral treatments (direct-acting anti-virals like protease NS3/4, polymerase NS5B, NS5A, entry inhibitors or other drugs like cyclophilin inhibitors, new interferons, immune modulators or therapeutic vaccine) are being rapidly developed (the approval of the first generation protease inhibitors is expected for spring 2011). The next step appears to be the combination of these oral drugs allowing a better safety and efficacy of the treatment.