Table 2.

Details of retrieved articles (listed chronologically)

Reference	Country	Aims	Intervention	Sample Characteristics	Data Collection Methods	Key Findings	Key Limitations
Bluthenthal et al., 1997	USA	To examine how law enforcement impacts PWID access to SEPs.	SEP	Unspecified number of PWID accessing SEPs in two cities.	Informal interviews and observation	Police interference with unsanctioned SEP limited access to these services among PWID and discouraged volunteer involvement. PWID cited fear of arrest as a primary reasons for not accessing syringe exchange services.	Authors do not clearly situate findings in relation to theoretical debates. Authors used mixed methods (including surveys) to determine impact of policing on SEP access, and their overview of the qualitative data was limited.
Finlinson et al., 1999	Puerto Rico	To explore PWID’s access to sterile syringes.	SEP	Unspecified number of PWID accessing 12 SEP sites. Sub-sample of 40 PWID (gender not specified) recruited through SEPs to participate in interviews.	Interviews and observation	Limited operating hours constrained access to syringe exchange services among PWID. Secondary syringe exchange was common among PWID, and viewed as a means to gain access to syringes when harm reduction services not available.	Authors do not clearly state theoretical perspective. Authors overlook participant perceptions of SEP.
Bourgois & Bruneau 2000	Canada	To explore HIV risks associated with SEP utilization.	SEP	Unspecified number of PWID accessing an SEP.	Observation	Local political conditions led produced restrictive SEP policies (one-to-one exchange) that limited access among PWID, and thus led to the development of informal exchange networks. Specific drug use practices (e.g., binge cocaine use) were critical in shaping access to syringe exchange services, and increased the potential from harm.	Authors provide only limited information regarding the study methodology, which makes it difficult to assess rigor.
Andrade et al., 2001	Brazil	To describe the opening of an SEP and impact of increased crack cocaine use on SEP utilization.	SEP	304 PWID accessing four SEPs. Sub-sample of 16 PWID (gender not specified) recruited through the SEPs to participate in in-depth interviews.	In-depth interviews and observation	Limited scope of syringe exchange services constrained access to syringes and led to syringe-sharing among PWID. Syringe-sharing not viewed as potentially harmful among many study participants. Shifts in local drug use patterns after the introduction of crack cocaine led to a substantial decrease in SEP utilization. Street-policing in response to increased crack cocaine use constrained access to SEP among PWID.	Authors draw on mixed methods (including surveys) and emphasized quantitative findings. Authors do not clearly state theoretical perspective, nor do they situate findings in relation to larger theoretical debates.
Porter et al., 2002	USA	To examine how PWID perceive and use services provided by SEPs.	SEP	46 PWID (25 male, 21 female), recruitment strategy not specified.	Semi-structured interviews	PWID viewed syringe exchange services as an intervention that mediated access to medical care and referrals. Authors develop a typology for medical care and referrals provided through syringe exchange services (from no access to a primary point of referral). PWID indicated that they trusted syringe exchange workers.	Potential for positive bias among study participants. Triangulation of data may be needed to verify referrals.
Rhodes et al., 2003	Russia	To explore factors that shape syringe exchange practices.	SEP	57 PWID (29 male, 28 female), recruited by outreach workers using purposive sampling.	Semi-structured interviews	Fear of being stopped by police exacerbated concerns about the risks of carrying injecting equipment, which in turn was linked to increased syringe sharing and in particular at the point of sale. Myth circulated that it is bad luck to buy syringes in advance. A minority of study participants reported that they had ever been to the two fixed site NEPs, and emphasized the fear of police as a primary barrier.	Limited data collection among regular SEP clients.
Spittal et al., 2004	Canada	To explore PWID’s access to sterile syringes.	SEP	Unspecified number of IDUs accessing mobile SEP.	Informal interviews and participant observation	Restrictive SEP policies (one-to-one exchange) undermined access to syringes. SEP workers issued “loaners” on an individual basis based on the perceived ability of PWID to return these syringes. Inconsistencies in issuing “loaners” led to tension with PWID, and constrained their access to syringes.	Limited data collection among PWID.
Cooper et al., 2005	USA	To explore how police crackdowns impact harm reduction practices.	SEP	40 PWID (21 male, 19 female), recruited through snowball sampling.	In-depth interviews	Intensified street-policing undermined the ability of injection drug users to practice harm reduction (e.g., rushed injections) and interfered with SEP access. Policing practices (e.g., random physical searches, surveillance) reconfigured how injection drug users perceived of their bodies and public spaces. PWID tried to avoid carrying syringes and obtained them primarily from peers prior to injecting.	Data collection did not begin until the police crackdown was underway, limiting the capacity document changes in SEP access.
Power et al., 2005	Russia	To describe how PWID experience SEP initiatives.	SEP	38 PWID (27 male, 11 female), recruitment strategy unspecified.	Semi-structured interviews and participant observation	Police harassment, including forced registration with drug use services, undermined access to SEPs. PWID trusted and valued outreach workers, and interacted with them to meet range of health and social care needs. PWID were reluctant to take referrals to other agencies due to concerns about registration with drug use services.	Limited data collection among regular SEP clients may negatively bias findings.
Kerr et al., 2007 ^a	Canada	To examine the impact of a SIF on overdose risk among PWID.	SIF	50 PWID (28 male, 21 female, 1 transgender), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	Participants felt that the immediacy of the response to overdoses was important, particularly in contrast to other settings. Participants articulated how taking their time—to ‘taste—at the SIF allowed them to implement common overdose prevention strategies and increase safety. Environmental supports mitigated fears of injecting alone without requiring them to share their drugs. Common narrative was that the facility saved lives that would otherwise be lost to overdose.	Potential for positive bias among study participants.
Kimber & Dolan, 2007	Australia	To explore shooting gallery attendance before and after the opening of a SIF.	SIF	17 PWID (13 males, 4 female) attending shooting galleries before and after the opening of a SIF, contacted through a peer recruiter and snowball sampling.	Semi-structured interviews	Shooting gallery attendance declined following the opening of supervised injection facility.	Article focused primarily on shooting gallery attendance. Limited discussion of how the opening of the SIF changed the structural-environmental context of the street-based drug scene. Authors do not state theoretical perspective or situating findings in relation to broader theoretical debates.
Sarang et al., 2008 ^b	Russia	To explore PWID’s access to sterile syringes.	SEP	209 PWID (140 males, 69 females) in three cities, recruited by outreach workers using snowball sampling methods.	Semi-structured interviews	Syringe exchange services rarely utilized due to range of factors, including: geographical barriers; and, fear of police interference. Restrictive syringe exchange policies (one-to-one exchange) limited the perceived benefits of SEP attendance (syringe access outweighed by time needed to access services).	Limited information provided regarding PWID encountered during ethnographic fieldwork.
Sherman et al., 2008	USA	To examine PWID’s experiences with peer-based overdose response.	Peer intervention	31 PWID (25 male, 6 female), contacted through SEP and researcher referral.	Semi-structured interviews	PWID weighed the fear of legal consequences (i.e., arrest) against desire to save lives when responding to overdose. Peer volunteers were able to intervene (e.g., administer naloxone, revive individuals) when responding to overdoses in diverse drug use settings.	Authors did not explore how recipients of naloxone experienced this intervention. Authors do not clearly state theoretical perspective. Potential for positive bias among peer volunteers.
Fairbairn et al., 2008 ^a	Canada	To examine female PWID’s experiences at a SIF.	SIF	25 female PWID, contacted through SIF and purposively sampled to reflect varying levels of SIF usage.	Semi-structured interviews	Women accessed SIF to escape structural and everyday violence within the street-based drug scene. Women were able to gain increased access over the injection process, and thereby minimize drug-related risks and exploitation. Women viewed this intervention as a place where they could receive range of supports, and emphasized that it was judgement-free.	Potential for positive bias among study participants. Study does not account for perspectives of women who face barriers to accessing facility.
Fast et al., 2008 ^a	Canada	To explore the delivery of safer injection education in a SIF.	SIF	50 PWID (28 male, 21 female, 1 transgender), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	Authors identified that gaps in safer injecting knowledge were linked to unsafe injecting practices among PWID.. Safer injecting education was accessible because it was delivered in a drug use setting (i.e., natural context of drug use). Study participants emphasized the supports provided by nurses, together with the broader environmental supports, created a safer injecting environment.	Potential for positive bias among study participants. Observation of nurse-delivered safer injecting education would have strengthened study findings. Theoretical perspective not clearly stated.
Small et al., 2008 ^a	Canada	To investigate the impact of a SIF on PWID’s access to care for injection-related infections.	SIF	50 PWID (28 male, 21 female, 1 transgender), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	Onsite nurses increased the accessibility of medical care and referrals, especially among PWID who were not otherwise seeking care for injection-related infections. Receipt of medical care in this setting was viewed as critical in addressing infections before they worsened. Participants emphasized the positive interactions with nurses in this setting.	Potential for positive bias among study participants. Theoretical perspective not clearly stated.
Ngo et al., 2009	Vietnam	To assess the effectiveness of a peer-based SEP.	Peer intervention; SEP	23 key informants (e.g., public health personnel, government officials, etc.) and unspecified number of IDUs.	Interviews, focus groups, and participant observation	Peer-run syringe exchange services, together with larger advocacy efforts, led to a change in community attitudes toward PWID. Police crackdowns were an ongoing barrier to peer syringe exchange services, with those arrested referred to mandatory drug treatment. Arrests led to a high turnover of peer volunteers, which interfered with the intervention’s sustainability.	Qualitative findings lack depth and nuance. Authors do not outline how data sources were triangulated. Theoretical perspective not clearly stated. Potential for positive bias among study participants.
Sherman et al., 2009	USA	To examine PWID’s experiences with peer-based overdose response.	Peer intervention	25 PWID (16 male, 9 female), contacted through intervention using convenience sampling.	Semi-structured interviews	Overdose prevention rarely discussed among PWID despite high prevalence of overdoses in local context. During the intervention, information regarding overdose prevention (peer-administered naloxone) was disseminated more quickly through peer networks and improved perceived safety of injecting.	Potential for positive bias among study participants. Study did not look at the impact of the program on overdoses or experiences of program recipients.
Krusi et al., 2009	Canada	To evaluate the impact of a supervised injecting room on HIV-positive PWID’s access to HIV care.	SIF	22 HIV-positive PWID (15 male, 7 female) accessing a care facility with a supervised injecting room, contacted through research advertisements posted at the facility.	Semi-structured interviews	Participants perceived this supervised injection services as increasing the safety associated with injection drug use (e.g., hygiene, overdose prevention, safety). Broader environmental supports strengthened this program (e.g., safer injecting education). Participants emphasized the positive relationship with nurses, and indicated that these mediated access to wider range of services.	Potential for positive bias among study participants. Theoretical perspective not clearly stated.
Small et al., 2009 ^a	Canada	To examine how SIF use impacts access to health and social services.	SIF	50 PWID (28 male, 21 female, 1 transgender), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	Supervised injection facility was viewed as “welcoming” environment where PWID could receive a range of supports, including medical care. Facility location was convenient to access, which reduced time and effort needed to access medical care. Study participants received a range of services and referrals in this facility, and indicated that they may not have otherwise received this care.	Potential for positive bias among study participants. Theoretical perspective not clearly stated.
Sarang et al., 2010 ^b	Russia	To explore impact of policing on drug and HIV risks, including access to sterile syringes.	SEP	209 PWID (140 males, 69 females) in three cities, recruited by outreach workers using snowball sampling methods.	Semi-structured interviews	Study participants expressed that the fear of arrest, detainment, and police violence constrained their access to syringe exchange services. Authors characterize the oppression of PWID as structural violence.	Limited data collection among regular SEP clients.
Fairbairn et al., 2010	Canada	To explore the context of assisted injection practices in the presence of a SIF.	SIF	20 PWID (7 male, 13 female) who required assistance injecting in the previous six months, recruited through cohort study and purposively sampled.	Semi-structured interviews	Participants reported that the rule prohibiting assisted injections at the SIF were a significant barrier to accessing that services.	Potential for positive bias among study participants. Theoretical perspective not clearly stated.
MacNeil & Pauly, 2011	Canada	To describe the meanings of SEPs among PWID.	SEP	33 PWID (23 male, 10 female), recruited using convenience sampling at four SEP sites	Semi-structured interviews	Participants situated their substance use within the context of social suffering. Syringe exchange services were viewed as a “safe haven”, and a place to receive a range of services and supports. Study participants emphasized how the non-judgemental approach taken by syringe exchange workers created a “stigma-free” space. Syringe exchange services helped to establish trust between PWID and health professionals, which was critical in mediating access to wider range of services.	Potential for positive bias among study participants.
Small et al., 2011a ^a	Canada	To examine PWID’s perspectives on the design and operation of a SIF.	SIF	50 PWID (28 male, 21 female, 1 transgender), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	Study participants emphasized how the SIF was a hygienic environment, and contrasted this setting with public injection settings. The overall design of the facility improved the ability to safely prepare drugs. Study participants indicated that the limited capacity of the facility was a barrier to access (during peak periods) and also noted that some operating procedures (prohibition of assisted injections) were a barrier.	Potential for positive bias among study participants.
Small et al., 2011b ^a	Canada	To examine how operating policies and local drug culture impact access to a SIF.	SIF	50 PWID (28 male, 21 female, 1 transgendered), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews and observation	Operating procedures disproportionately impacts those who share particular drugs (e.g., solid pills that must be diluted and cooked) and those individuals may opt to use elsewhere. Individuals taking longer time to inject impeded turnover, particularly during peak periods. Longer waits were viewed as a significant barrier, with PWID opting to inject elsewhere due to the urgency of their needs (e.g., ‘dopesickness’) Rules prohibiting assisted injections were a significant barrier to services, especially among women.	Authors may overlook additional barriers due to limited observation outside of SIF.
McLean, 2012	USA	To explore the social geography of SEPs.	SEP	Unspecified number of PWID accessing an SEP. Sub-sample of 11 PWID (gender unspecified) recruited through SEP to participate in semi-structured interviews.	Semi-structured interviews and participant observation	Study participants access syringe exchange services to meet a broad range of health and social care needs (‘geography of survival’), and the parameters of service delivery allowed them to have structured relationships with staff. Syringe exchange site served as an informal marketplace where a wide range of resources could be exchanged. Study participants indicated that the SEP was a “safe space” that they could access within the broader context of poverty, homelessness, and displacement. Safety from police harassment was identified as a particularly salient theme.	Potential for positive bias due to limited observation in other settings.
Parker et al., 2012	Canada	To explore access to harm reduction services among PWID in rural areas.	SEP	115 PWID (gender unspecified), recruited through fixed site and mobile SEPs and snowball sampling.	Semi-structured interviews	Study participants in urban areas had increased access to syringes due to availability of SEPs, while outreach services did increase access in rural areas. Syringes were reused or shared by study participants when unable to access services (e.g., outside of operating hours). SEPs were viewed as a unique and supportive space where PWID could receive a range of services and supports, and interact with SEP workers and nurses without experiencing stigma.	Potential for positive bias among study participants. Theoretical perspective not clearly stated.
Small et al., 2012a	Canada	To explore the development, operation, and impact of an assisted injecting intervention.	Peer intervention	10 peer outreach workers and 9 PWID programme participants (gender unspecified). Unspecified number of programme participants observed.	In-depth interviews and observation	Peer support intervention was critical in mediating access to safer injecting education in natural drug use settings (e.g., alleyways, etc.). Assistance provided by peers was viewed as critical in decreasing reliance upon ‘hit doctors’ in the street-based drug scene, and thus minimizing violence and exploitation.	Potential for positive bias among study participants. Limited data collection among program recipients.
Small et al., 2012b ^a	Canada	To examine how PWID’s perceptions of risk shape SIF attendance.	SIF	50 PWID (28 male, 21 female, 1 transgendered), contacted through SIF and purposively sampled to reflect varying levels of use	Semi-structured interviews	SIF was viewed as the “proper” place to inject, and contrasted with other injecting settings. Study participants viewed SIF as critical in minimizing risks associated with injection drug use (e.g., overdose, injection-related infections, etc.) by allowing them to inject “properly”. Participants emphasized the importance of a sanctioned injecting environment, and noted the benefits of police not interfering with intervention. Participants cited safety as a primary motivator of accessing SIF, with safety encompassing a range of meanings.	Potential for positive bias among study participants.

SIF: supervised injection facility; SEP: syringe exchange programme; PWID: people who inject drugs.

Based on data collected as part of an evaluation of a supervised injection facility.

Based on data collected as part of a larger study of HIV risk in three Russian cities.