Spontaneous loss of hepatitis C virus RNA from serum is associated with genotype 1 and younger age at exposure.

A variety of factors have been associated with spontaneous loss of hepatitis C virus (HCV)-RNA from serum, including infecting HCV type, although results are conflicting. This study aimed to investigate further whether infecting HCV type was linked to spontaneous loss of HCV-RNA. Serum samples from 321 untreated HCV antibody positive patients presenting at the Hepatology clinic at Addenbrooke's Hospital, Cambridge between 2004 and 2007 were tested. These individuals were classified either as HCV antibody and HCV-RNA positive (viremic, n = 219) or HCV antibody positive and repeatedly HCV-RNA negative (non-viremic, n = 102). Infecting HCV type was identified by genotyping (viremic) or serotyping (non-viremic). Binomial regression analysis investigated the independent effect of HCV type on spontaneous loss of HCV-RNA from serum by comparing the two groups. Ninety-one percent of patients were found to be either genotype 1 or genotype 3. The prevalence of type 1 infection was greater among non-viremic (64.5%) than viremic individuals (45%). After controlling for the effects of potential confounding factors, multivariable analyses showed that individuals with type 1 infections were more likely to be non-viremic than genotype 3 infections (RR = 2.07; 95% CI: 1.25, 3.43; P = 0.005). Individuals infected at an older age were also less likely to become HCV-RNA negative spontaneously (RR = 0.42 comparing those infected at ≥20 years of age against those infected at <20 years of age, 95% CI: 0.25, 0.72; P = 0.002). In conclusion, the results suggest that HCV genotype 1 infections are more likely than genotype 3 infections to become spontaneously non-viremic, as are infections acquired at younger age.