Needle and syringe programs (NSPs) were first initiated in Australia in 1986 and are considered a success story. Over the past 10 years the prevalence of HIV has remained stable at roughly 1%, while the prevalence of HCV infection is about 60%. Injecting habits, including needle sharing, have also remained stable. Using a mathematical model, it was estimated that the NSPs have averted 32,050 new HIV infections and 96,667 HCV infections over the past 10 years. For every one dollar invested in NSPs, 0.2 days of disability-adjusted life was gained and more than four dollars were returned in healthcare cost-savings over ten years, mainly due to savings related to HCV associated morbidity.

Effectiveness of NSPs in reducing incidence of HIV among IDU was also demonstrated in Tallinn, Estonia. Between 2003 and 2009 there has been a dramatic increase in numbers of needles distributed (from 18,000 to over 770,000). Repeated cross-sectional surveys were conducted and HIV incidence was estimated using prevalence data stratified by time at risk (years of injecting) and assuming that HIV prevalence differences between the years of IDU duration strata represent incident HIV infections. Between 2005 and 2009 the incidence of HIV infection among new injectors (who started injecting drugs within the previous 5 years) decreased decreased from 18 /100 person-years to 7.5 /100 person-years.

Qualitative research among IDU in North-West Russia, highlighted problems with access to prevention and care services. Especially in small towns there were issues with geographical accessibility and confidentiality. IDU expressed a strong preference for a more personalized approach to prevention.

So far, only few data are available on IDU in sub-Saharan Africa. In 2007, a survey was conducted among IDU in Zanzibar. The survey was the first in Africa to recruit IDU through respondent driven sampling. Nearly all IDU were male (97%). More than half of them shared needles and 3% were involved in direct blood sharing. HIV prevalence was 16% and HIV infection was associated with high risk behaviour. Prevalence of HCV infection was 26%, substantially lower than in Australia. There was no obvious explanation for the difference in HCV prevalence between Zanzibar and Australia.

Intravenous use of crystal methamphetamine is on the rise in many settings and appears to affect care of HIV infection. A study among treatment naïve HIV infected IDU in Vancouver, revealed that the use of crystal methamphetamine significantly delayed viral suppression when starting HAART. It was unclear whether this a direct effect of CM or an indirect effect through the psychopharmacological effects of CM on treatment adherence.