The sole objective of this guideline is to summarize and educate about highly useful concepts for scaling up harm reduction in any country.

The Joint Action on HIV and Co-Infection Prevention and Harm Reduction (HA-REACT) is addressing the gaps that exist in the prevention of HIV and other co-infections, especially tuberculosis and viral hepatitis, among people who inject drugs. Among the work packages (WP) of this Action, WP5 was focused on scaling up harm reduction, and one of its activities was an assessment of people who inject drugs (PWID), including epidemiology and HR interventions in selected focus countries. This guideline has been drafted within the context of those activities and with the objective of serving as a first point of contact with PWID calculation methodologies and the subsequent measurement of that population’s Harm Reduction Coverage.