Both studies collect data and conduct follow-ups in a harmonized manner to facilitate combined analyses. At baseline and every six months thereafter, participants answer an interviewer-and nurse-administered questionnaire pertaining to socio-demographic information, sex-and drug-related risk behaviors, housing conditions, and experiences with the healthcare and criminal justice systems. Participants provide blood samples for serologic HIV testing (or HIV disease monitoring if positive) and HCV testing at each visit. Participants receive $30 CAD as remuneration at each visit and are offered referrals to addiction treatment and other health services. The VIDUS and ACCESS studies have annual approval from the Providence Health Care Research/University of British Columbia Research Ethics Board. Data for these analyses were collected from December 2005 to May 2015.
