BACKGROUNDReinfection with hepatitis C virus (HCV) following successful treatment with direct-acting antivirals (DAAs) is a threat to achieving the World Health Organization viral hepatitis elimination goals. Given the limited data among people who inject drugs (PWID) from low-and-middle-income countries (LMICs), we characterized HCV reinfection among PWID in Imphal, India.METHODSOur study population included PWID who achieved a sustained virologic response (SVR) after DAA treatment at community-based treatment programs located in harm reduction centers. Reinfection rates per 100 person-years (PY) were calculated overall and by select characteristics. Poisson regression was used to estimate incidence rate ratios and correlates of reinfection.RESULTSAmong 1267 PWID who achieved SVR and were screened for this study, 315 instances of reinfection were documented over 2395 PY of follow-up with an incidence rate (IR) of 13.2 per 100 PY (95 % CI: 11.8, 14.7). The incidence of reinfection was highest among those 18-24 years old (20.0 per 100 PY, 95 % CI: 16.9, 23.8) and in multivariable analysis, age remained independently associated with reinfection risk. Those 18-24 years old had the highest incidence (adjusted incidence rate ratio (aIRR) compared to 45-54 years: 4.94 [95 % CI: 2.59, 9.42]). The use of medication for opioid use disorder (MOUD) was also associated with reinfection in those reporting recent injection (aIRR: 1.57 [95 % CI: 1.19, 2.09]).CONCLUSIONSThe high reinfection rate among PWID in Imphal, a setting with comprehensive harm reduction programs, highlights the need to integrate and innovate models of HCV care and harm reduction service delivery with a particular emphasis on young PWID.