Foreword: Public health, public policy, politics and policing

Harm reduction, as a public health, encompasses a wide and diverse array of approaches aimed at minimizing individual and collective negative impacts of risky behaviours. Road safety measures such as speed limitation and the enforcement of seat belt and motorcycle helmet legislation are examples of such measures. In the realm of HIV/AIDS, harm reduction approaches have had significant impacts on HIV transmission among men who have sex with men (MSM) and injecting drug users (IDUs) as well as in the context of heterosexual and transactional sex. Elimination of risk, vulnerability and impact will remain remote goals until a cure and highly effective vaccines become available, and most-at-risk populations are no longer subjected to discrimination and social exclusion. Until then, harm reduction approaches have proven the approaches of choice, demonstrated by declining HIV prevalence and incidence over the last two decades in populations where prevention and early access to treatment have been instituted at scale.Evidence abounds supporting the introduction in public policy and in practice of measures aimed principally at minimizing the spread of HIV (and Hepatitis B and C) resulting from the sharing of unsterile paraphernalia. Those who have patiently and rigorously collected, analysed and disseminated this evidence have produced a very robust body of evidence for policy change. Often in adverse environments, they have established that making sterile injection equipment available to drug users and switching from injection – involving high risks of blood-borne contamination – to less harmful forms of drug use, including the oral administration of opiate substitutes, substantially lowers risk and transmission of HIV. They have repeatedly shown that these measures are effective on the individual and community levels when combined with individual counselling, community networking and public information. Notably, they have also documented that these approaches do not impact