The Scientific Evaluation of Supervised Injecting (SEOSI) study began in 2003 and was a cohort study that evaluated the use of Insite, North America’s first medically supervised injecting facility. More than 45 research studies evaluating Insite have been published in such prestigious peer-reviewed journals as The Lancet, The New England Journal of Medicine, and the British Medical Journal. SEOSI has also contributed to a number of policy developments, including the Supreme Court ruling allowing Insite to remain fully operational in Vancouver, BC.

Similarly to the BC Centre on Substance Use’s ongoing cohort studies (Vancouver Injection Drug Users Study, AIDS Care Cohort to Evaluate Exposure to Survival Services, and At-Risk Youth Study), SEOSI was a longitudinal study made up of individuals who represent a larger population and are tracked over time. SEOSI participants were randomly recruited from Insite and formed a representative sample of all Insite clients. SEOSI participants completed both an interviewer-administered questionnaire and a clinic visit with a nurse every six months, including HIV testing. Interviews covered topics related primarily to the use of Insite, including how use of the facility impacted personal drug use practices such as syringe sharing and public drug use, HIV risk behaviour, and access to health and social services.


The objective of SEOSI research was to evaluate the use and impact of North America’s first medically supervised injecting site. SEOSI research focused on the following specific objectives:

  • To examine how use of the facility affected personal drug use and health behaviours, such as syringe sharing and enrolment into drug treatment programs; and
  • To better understand the overall impact supervised injecting facilities may have on individual- and community-level drug use patterns including public drug consumption, initiation and cessation of drug use, and morbidity and mortality.


Briefly, findings of the evaluation found that Insite had an overall positive impact on the Downtown Eastside community. Specifically, during the evaluation period Insite was found to:

  • Be used by the people it was intended for,
  • Reduce HIV risk behaviour,
  • Promote uptake of addiction treatment,
  • Improve public order,
  • Reduce overdose risk and death,
  • Provide a safe place for women to inject drugs,
  • Offer medical care for injection-related infections,
  • Not lead to increased drug use or increased crime, and
  • Be cost-effective.

Read the full report here. Read the research summary here. Both the report and research summary are also available in French (links are provided below).


  • Portland Hotel Society (PHS)
  • Providence Health Care (PHC)
  • University of British Columbia (UBC)
  • Vancouver Coastal Health (VCH)


  • Canadian Institutes of Health Research (CIHR)


To learn more about SEOSI, follow the links below.

Full report [ English | French ]

Research summary [ English | French ]

BC Centre on Substance Use

400-1045 Howe St, Vancouver, BC V6Z 2A9

E: [email protected] | T: (778) 945-7616 | F: (604) 428-5183

24/7 Addiction Clinician Support Line: (778) 945-7619

Online Addiction Medicine Diploma: [email protected].

website logos footer

Copyright © 2023, BC Centre on Substance Use