“…The independent variables, were selected based on previous published literature and included: age, sex, education level, income level (Tomans per month, although the Rial is the official currency, Iranians use the Toman in everyday life), amount spent on substance consumption per month, living conditions, drug injection history, prison history, mental illness history, heart disease, infectious diseases, self-reported health status (poor, moderate, good), previous Covid-19 infection (asking if they had ever tested for Covid-19), arrest and detoxification camp during Covid-19 pandemic, ethnicity, marital status, access to COVID-19 vaccination center, current living partner. The attitude towards Covid-19 vaccination was measured by using the 5-point Likert Covid -19 vaccination attitude scale for adults (Co-VASA), ranging from completely disagree (score = 1) to completely agree (score = 5) [ 38 ].…”