Globally, fewer than 1 in 10 injecting drug users (IDUs) are covered by effective HIV prevention interventions, with just 5% of injections likely covered by a syringe provided from a needle and syringe programme (NSP). Only eight clients receive opioid substitution therapy (OST) for every 100 IDUs, while only 4 of every 100 HIV-positive IDUs receive antiretroviral therapy (ART). While all these interventions can have a stand-alone effect, they must be used together to substantially reduce HIV transmission among IDUs. This is a key message of a new paper in The Lancet Series on HIV in People Who Use Drugs, written by Professor Louisa Degenhardt, National Drug and Alcohol Research Centre, University of New South Wales, Sydney, Australia, and colleagues. The paper also shows the need for policy, legal and other structural changes as a core element of HIV prevention for IDUs.
The reviewed evidence in the paper shows the critical importance of scaling-up NSP, OST and ART for IDUs around the world. Individual or group based psychosocial therapy to address risky behaviours can reduce both injection and sexual transmission risk. IDUs themselves have a key role in developing such strategies, including through peer based interventions. The authors emphasise the need to better target HIV prevention strategies for amphetamine and cocaine injectors. They write: "Model projections suggest high coverage of ART, OST and NSP in combination are important for reduction of incidence of HIV infection in IDUs by more than 50%; very high intensity and coverage of single interventions is necessary to achieve similar effects; short-term, small-scale, single interventions are unlikely to be effective."
The authors also stress the importance of structural interventions, ie, those that operate at the population or community level. Strategies such as providing clean needles in prisons can reduce HIV transmission without increasing injection rates. Observational studies suggest providing supervised injecting centres with clean equipment attracts IDUs at greatest risk of HIV, who can also be engaged in health and drug treatment services to further reduce risky behaviours. Peer-based interventions which bring about change at the level of the social network can also reduce needle sharing and risky sexual behaviour. Policy interventions that alter the legal environment are also needed and can have a positive community-level effect. For example, relaxing of legal restrictions on the provision of sterile needles and syringes reduces risky behaviour in IDUs without adverse effects.
Also highlighted in this second paper is that current resources provided for research and implementation of the response to HIV infection in IDUs are insufficient: according the the International Harm Reduction Association, an estimated US$0•03 are spent per IDU per day, far short of the amount needed. UNAIDS estimated that in 2009, 19% of global resources needed for prevention of HIV infection should be targeted towards IDUs, yet as little as 1% was allocated in this way.
The authors conclude: "Prevention of HIV infection needs high coverage and combined approaches. Single interventions, even at high coverage, are likely to achieve only modest reductions in HIV transmission, particularly in settings with very high levels of HIV risk behaviours. Governments, policy makers, and public-health officials must be engaged and convinced of the importance of scaling up."
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