Viral hepatitis C gets personal--the value of human genomics to public health.

About 180 million people worldwide are chronically infected with hepatitis C virus (HCV), with 3-4 million newly infected each year. Only 15-25% of acute HCV infections clear spontaneously, and the remainder persists as chronic HCV infection. More than 350,000 people die every year from hepatitis C-related liver failure and cancer. There is currently no vaccine and the standard-of-care therapies--peg-interferon alpha (pegIFN) plus ribavirin (RBV)--are expensive and have serious side effects. Also, they may be effective in only 40-50% of patients infected with HCV genotype 1, the most common HCV genotype in the US. Interleukin 28B (IL28B) genotype was recently and convincingly associated with response to pegIFN and RBV therapy. It has emerged as a robust pretreatment predictor of sustained virological response (SVR, i.e. virologic clearance) to pegIFN and RBV as well as to new triple therapy regimens that include a direct-acting antiviral agent with pegIFN and RBV and increase SVR rates as much as 75% in patients infected with HCV genotype 1. Testing for IL28B genotype may contribute to clinical decision-making and could inform clinical guidelines and public health policies.