The introduction of nucleic acid amplification assays detecting HCV genomes with high sensitivity, i.e., <10 virus genome equivalents (vge) or copies/ml or <2.5 vge/μg RNA (<2 IU/ml), revealed that HCV persists at low levels (usually below 100 vge/ml) for years after clinical resolution of hepatitis either spontaneously or due to treatment with interferon-α (IFN) alone or pegylated IFN/ribavirin (PegIFN/R) [6], [7]. Here, IFNA1 is linked to hepatitis A virus infection.