Methods: Data were drawn from the International Collaboration of Incident HIV and Hepatitis C in Injecting Cohorts (InC3 Study) including nine prospective cohorts of people who inject drugs. Factors associated with high HCV-RNA levels (>5.6 log IU/mL=400,000 IU/mL) during the first two months post-infection Staurosporine solubility dmso were assessed. Among those with viral persistence, factors associated with high HCV-RNA levels (>5.6 log IU/mL) at one year (8-16 month window) post-infection were also assessed. Logistic regression was used in analyses. Results: Among participants with detectable HCV-RNA during the first two months post-infection (n=178), interferon lambda 3 (IFNL3) CC genotype (vs. TT/CT; adjusted
odds ratio [AOR]: 3.05; 95%CI: 1.48, 6.27; P=0.002) was the only factor associated with high HCV-RNA levels. Among those with persistent HCV infection (n=308), male sex (vs. female, AOR: 1.93; 95%CI: 1.01, 3.69; P=0.046), IFNL3 CC genotype (vs. TT/CT; AOR: 2.48; 95%CI: 1.42, 4.35; P=0.001), HIV co-infection (vs. no HIV; AOR: 3.27; 95%CI: 1.35, 7.93; P=0.009), and HCV genotype G2 (vs. G3; AOR: 5.40; 95%CI: 1.63, 17.84; P=0.006) were independently associated with higher HCV-RNA levels. HCV G1 (vs. G3; AOR: 1.87; 95%CI: 0.99,
3.55; P=0.054) trended towards being associated with higher HCV-RNA. Conclusion: HCV-RNA levels were independently associated with IFNL3 genotype during the first two months post-infection and IFNL3 genotype, sex, HIV co-infection, and HCV genotype Ensartinib in vitro at one year post-infection. During chronic infection, factors influencing HCV-RNA levels exert their effects as early as one year following infection. Further research is needed to understand the interplay between the role of gender, host genetics and viral genotype in the pathogenesis of HCV infection. Disclosures: Palmatine Arthur Y. Kim – Consulting: Abbvie Pharmaceuticals, Gilead Pharmaceuticals; Grant/Research Support: Bristol-Myers Squibb, Gilead Pharmaceuticals Barbara H. McGovern – Employment: AbbVie Andrew R. Lloyd – Grant/Research Support: Merck Maria Prins – Speaking and Teaching:
msd, roche Gregory J. Dore – Board Membership: Bristol-Myers Squibb, Roche, Gilead, Merck, Janssen, Abbvie; Grant/Research Support: Janssen, Bristol-Myers Squibb, Vertex, Roche, Gilead, Merck, Abbvie; Speaking and Teaching: Roche, Merck, Janssen Jason Grebely – Advisory Committees or Review Panels: Merck, Gilead; Grant/ Research Support: Merck, Gilead, Abbvie, BMS The following people have nothing to disclose: Behzad Hajarizadeh, Bart P. Grady, Kimberly Page, Andrea Cox, Thomas M. Rice, Rachel Sacks-Davis, Julie Bruneau, Meghan D. Morris, Janaki Amin, Janke Schinkel, Tanya L. Applegate, Lisa Maher, Margaret Hellard, Ronald Geskus Background: Daclatasvir (DCV) is an HCV NS5A inhibitor with potent antiviral activity and broad genotype coverage. Exhaustive information about resistance-associated variants (RAVs) to DCV is available for GT1, but current migratory waves are increasing interest in GT4.