Hepatitis C virus (HCV) infections in people who inject drugs (PWID) can now be treated and cured. However, the impact that HCV treatment has on drug-user health, practices and wellbeing is not known. The aim of this research was to understand the non-clinical impact that HCV treatment has in PWID and their reasons for accessing and completing treatment. Participants aged 25-67 years who had injected opioids or stimulants (currently or in the past) and had completed direct-acting antiviral treatment were recruited from seven European countries. Participants completed a 30-min online survey administered face-to-face between September 2018 and April 2019. The questionnaire responses were used to assess the mental and physical impact of having...