Previously published United Nations (UN) guidance documents describe the content of effectiveHIV and HCV prevention interventions for people who inject drugs, in the context of harm reduction (15) and HIV prevention for key populations (Table 1). (9) UN guidance is also grounded in an approach expressed in the critical enablers described in Table 2—strategies, activities and approaches to increase the accessibility, acceptability, coverage, quality and uptake of interventions and services for key populations. (9) This tool offers practical advice on how to implement these programmes and these approaches for and with people who inject drugs, across the full continuum of HIV and HCV prevention, diagnosis, treatment and care, aligned with UN guidance. It contains examples of good practice from around the world that may support efforts in planning programmes and services, and describes issues that should be considered and how to overcome challenges.

This tool does not seek to ignore the complex policy and legislative environment around drugs and injecting drug use in most countries, nor the need for advocacy to confront the stigma, discrimination and human-rights violations faced by people who inject drugs. However, it aims primarily to address the question: what can we do now, with the resources we have, in the kinds of environments we face, to prevent the spread of HIV and hepatitis C among people who inject drugs?

The tool describes how services can be designed and implemented to be accessible and acceptable to people who inject drugs. This requires respectful and ongoing engagement, and this publication gives particular attention to programmes run in close partnership with, or by, organizations of people who use drugs. It is itself the product of a collaborative process including people who inject drugs, advocates, service-providers, researchers, government officials and nongovernmental organizations (NGOs) from around the world, as well as United Nations agencies and other development partners.

The intended users of this tool are public-health officials and managers of HIV and harm reduction programmes; nongovernmental, community and civil-society organizations, including networks of people who use drugs; and health workers. It will also be of interest to advocates and activists for the rights of people who use drugs, and to international funding agencies and health policy-makers.

This tool is one of a series of publications that address HIV prevention with key populations. The others in this series are Implementing comprehensive HIV and STI programmes with sex workers: practical guidance from collaborative interventions (WHO; 2013), informally known as the sex worker implementation tool or SWIT; Implementing comprehensive HIV and STI programmes with men who have sex with men: practical guidance for collaborative interventions (UNFPA; 2015) or MSMIT; and Implementing comprehensive HIV and STI programmes with transgender people: practical guidance for collaborative interventions (UNDP; 2016) or TRANSIT. In keeping with this style, users of this tool may wish to refer to it informally as the IDUIT.