Are needle and syringe programmes associated with a reduction in HIV transmission among people who inject drugs: a systematic review and meta-analysis.

BACKGROUND: Needle and syringe programmes (NSP) aim to reduce the risk of HIV by providing people who inject drugs (PWID) with sterile injecting equipment. A recent review of reviews (ROR) concluded that there was only tentative evidence to support the effectiveness of NSP in reducing HIV. We carried out a systematic review and meta-analysis to assess the association between NSP and HIV transmission. METHODS: Relevant primary articles presenting data on the risk of HIV transmission associated with NSP were identified in two stages: (i) from reviews identified in two published RORs (covering the period 1980-2008); and (ii) a literature search of CINAHL, Cochrane Library, EMBASE, MEDLINE and PsychINFO for primary articles published since the most recent high quality review (covering the period 2008-12). Study results were synthesized using random-effects meta-analysis. RESULTS: There were 12 studies comprising at least 12 000 person-years of follow-up. Exposure to NSP was associated with a reduction in HIV transmission: pooled effect size 0·66 [95% confidence interval (CI) 0·43, 1·01] across all studies, and 0·42 (95% CI 0·22, 0·81) across six higher quality studies (according to the Newcastle-Ottawa tool). CONCLUSIONS: There is evidence to support the effectiveness of NSP in reducing the transmission of HIV among PWID, although it is likely that other harm reduction interventions have also contributed to the observed reduction in HIV risk. NSP should be considered as just one component of a programme of interventions to reduce both injecting risk and other types of HIV risk behaviour.

Interventions to prevent HIV and Hepatitis C in people who inject drugs: a review of reviews to assess evidence of effectiveness.

BACKGROUND: Injecting drug use is a major risk factor for the acquisition and transmission of HIV and Hepatitis C virus (HCV). Prevention of these infections among people who inject drugs (PWID) is critical to reduce ongoing transmission, morbidity and mortality. METHODS: A review of reviews was undertaken involving systematic literature searches of Medline, Embase, CINAHL, PsychINFO, IBSS and the Cochrane Library (2000-2011) to identify English language reviews regarding the effectiveness of harm reduction interventions in relation to HIV transmission, HCV transmission and injecting risk behaviour (IRB). Interventions included needle and syringe programmes (NSP); the provision of injection paraphernalia; opiate substitution treatment (OST); information, education and counselling (IEC); and supervised injecting facilities (SIFs). Reviews were classified into 'core' or 'supplementary' using critical appraisal criteria, and the strength of review-level evidence was assessed. RESULTS: Twelve core and thirteen supplementary reviews were included. From these reviews we identified: (i) for NSP: tentative review-level evidence to support effectiveness in reducing HIV transmission, insufficient review-level evidence relating to HCV transmission, but sufficient review-level evidence in relation to IRB; (ii) for OST: sufficient review-level evidence of effectiveness in relation to HIV transmission and IRB, but tentative review-level evidence in relation to HCV transmission; (iii) for IEC, the provision of injection paraphernalia and SIFs: tentative review-level evidence of effectiveness in reducing IRB; and either insufficient or no review-level evidence for these interventions in relation to HIV or HCV transmission. CONCLUSION: Review-level evidence indicates that harm reduction interventions can reduce IRB, with evidence strongest for OST and NSP. However, there is comparatively little review-level evidence regarding the effectiveness of these interventions in preventing HCV transmission among PWID. Further studies are needed to assess the effectiveness and impact of scaling up comprehensive packages of harm reduction interventions to minimise HIV and HCV transmission among PWID.