The impact of the COVID-19 pandemic on social determinants of health, mental health, and substance use among key populations affected by sexually transmitted and blood-borne infections in Canada

We assessed the impact of the COVID-19 pandemic on social determinants of health, mental health, substance use, and access to mental health and harm reduction services among key populations disproportionately impacted by sexually transmitted and blood-borne infections (STBBI). Online surveys (2021‒2022) were conducted in Canada among people who use drugs or alcohol (PWUD); African, Caribbean, and Black people (ACB); and First Nations, Inuit, and Métis peoples (FNIM). Descriptive analyses were conducted on social determinants of health, substance use, and access to services, stratified by changes in mental health status since the start of the pandemic. A total of 3773 participants (1034 PWUD, 1556 ACB, and 1183 FNIM) completed the surveys, with 45.6