Article

Frequent Longitudinal Sampling of Hepatitis C Virus Infection in Injection Drug Users Reveals Intermittently Detectable Viremia and Reinfection

University of California San Francisco, San Francisco, CA.
Clinical Infectious Diseases (Impact Factor: 9.42). 10/2012; 56(3). DOI: 10.1093/cid/cis921
Source: PubMed

ABSTRACT Background. Detection of hepatitis C virus (HCV) reinfection and intercalation (i.e., intermittent recurrent bouts of viremia with homologous virus interspersed with aviremic periods) requires extensive and frequent evaluation and viral sequencing.Methods. HCV infection outcomes were studied prospectively in active IDU with recurrent HCV RNA positive tests after serial negative results. HCV viremia and viral sequences (Core/E1) were assessed from monthly blood samples.Results. Viral clearance, reinfection and intercalating infection were all detected. Among 44 participants with apparently resolved HCV (26 incident HCV clearers and 18 enrolled with already resolved infection), 36 (82%) remained persistently HCV RNA negative, but 8 demonstrated intermittent recurrent viremia. Four of these (50%) had confirmed reinfection with a heterologous virus; three demonstrated viral intercalation, and one was not classifiable as either. Estimated incidence of first reinfection was 5.4/100 PY; (95% CI, 2.0, 14.5). Six (75%) participants, including three of four of those with reinfection, demonstrated sustained viral clearance for a median of 26 months since last HCV RNA test.Conclusions. These results show that frequent monitoring and viral sequencing are required to correctly assess HCV outcomes and estimate incidence of reinfection (which was previously overestimated). Sustained clearance may take many months and occur after episodes of reinfection and viral intercalation. Three of four subjects who had confirmed reinfection showed evidence of long term clearance. Viral intercalation occurs with significant frequency. Further studies of these events, especially immunological are needed to inform HCV clinical care and vaccine development.

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