[Commentary] EMERGING ROLE OF SUPERVISED INJECTING FACILITIES IN HUMAN IMMUNODEFICIENCY VIRUS PREVENTION

During the last two decades, the human immunodeficiency virus (HIV) epidemic has transitioned from primarily a sexually driven epidemic to one where syringe sharing among illicit injection drug users (IDU) contributes to a significant proportion of new infections 1. Recently, the Joint United Nations Programme on HIV/AIDS estimated that one-third of new cases outside sub-Saharan Africa are the result of the use of contaminated syringes 2. In North America, injection drug use accounts for one in four cases of HIV; in some of the world's fastest-spreading outbreaks, such as eastern Europe and Central Asia, more than 80% of all HIV infections occur among IDU 2. In response to a large volume of favourable research, international public health consensus bodies such as the World Health Organization (WHO) have endorsed needle and syringe programmes strongly as an evidence-based HIV prevention intervention. However, due in part to a limited evidence base, medically supervised safer injecting facilities (SIF) have been controversial, and political support in many jurisdictions has been limited 3-5. A recent illustrative example occurred at the XVII International AIDS Conference in Mexico City in August 2008, where an original draft of a WHO report on evidence-based HIV prevention measures endorsed SIF unequivocally as a ‘priority intervention’, noting ‘they enable known, WHO-recommended harm reduction interventions to be delivered and used in a safe environment with the aim of reaching the most marginalized and vulnerable of injecting drug users’6. However, after apparent pressure from the Canadian federal government 7, the WHO documents were amended online to read that there ‘was not enough evidence’ regarding the role of SIF in HIV prevention 8. In this issue of Addiction, Bravo et al.9 provide evidence supporting SIF as an effective intervention to reduce HIV risk behaviours. In their cross-sectional study of 249 Spanish IDU evaluated as part of a community-recruited cohort, individuals who reported using one of the five SIF in Barcelona and Madrid were significantly less likely to report borrowing used syringes. This association persisted in multivariate analyses which adjusted for a range of potential confounders, including demographic characteristics and measures of social vulnerability. Although the observational and cross-sectional nature of the study requires great caution when interpreting the results, Bravo et al.'s finding of a beneficial effect of SIF attendance on patterns of HIV risk behaviour is consistent with preliminary evaluations of SIF in Europe 10 and two quantitative epidemiological analyses from prospective cohorts of IDU in Vancouver, Canada 11, 12. First, among individuals participating in the Vancouver Injecting Drug Users Study (VIDUS), a community-recruited cohort of IDU, regular use of the local SIF was associated independently with reduced odds of syringe sharing 11. Importantly, the longitudinal nature of this cohort allowed for an evaluation of syringe-sharing patterns before the opening of the SIF and demonstrated that the reduction among SIF users coincided with the programme's opening 11. Similarly, among a cohort of IDU recruited randomly from the Vancouver SIF, while there was no relationship with syringe-lending among HIV-seropositive individuals, SIF use was again associated with a reduced likelihood of syringe-borrowing among HIV-seronegative participants 12. To put the similarities among this emerging literature into context, we constructed a random-effects meta-analysis model 13 to produce a pooled estimate of the relationship between SIF use and syringe sharing. Our analysis included all available peer-reviewed estimates described above 9, 11, 12. As shown in Figure 1, the pooled estimate of 0.31, representing a 69% reduction in the likelihood of syringe sharing among SIF users, was statistically significant (95% confidence interval: 0.17–0.55). Forest plot of the effects of safer injecting facilities use on human immunodeficiency virus (HIV) risk behaviours among injection drug users in three cohorts (n = 1262); CI: confidence interval Although meta-analyses of observational studies contain the same cautions and limitations as their component studies 9, 11, 12, this analysis demonstrates the consistent pattern emerging in the quantitative literature assessing the impact of SIF use on syringe sharing. Because an increase in condom use has also been associated with the use of SIF 14, these programmes appear to have an emerging role in HIV prevention. The study by Bravo et al. makes an important contribution to this emerging literature which, unless contradictory findings are reported from other settings, the weight of evidence may eventually compel evidence-based public health agencies such as WHO to support the expanded use of SIF as a strategy to help reduce syringe sharing among IDU. The authors acknowledge the support for the evaluation of Insite, Vancouver's SIF, provided by Vancouver Coastal Health and the Canadian Institutes of Health Research (CIHR) (Grant HPR-85526). Initial support for the SIF evaluation was provided by Health Canada. Additionally, the authors acknowledge the support provided by a CIHR Team Grant (RAA-79918). The authors would also like to thank Deborah Graham, Leslie Rae, Caitlin Johnston, Steve Kain and Calvin Lai for their research and administrative assistance. None.

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