Objective: To provide global estimates of the prevalence of injecting drug use (IDU) and HIV prevalence among IDU, in particular to provide estimates for developing and transitional countries.
Methods: Collation and review of existing estimates of IDU prevalence and HIV prevalence from published and unpublished documents for the period 1998–2003. The strength of evidence for the information was assessed based on the source and type of study.
Results: Estimates of IDU prevalence were available for 130 countries. The number of IDU worldwide was estimated as approximately 13.2 million. Over ten million (78%) live in developing and transitional countries (Eastern Europe and Central Asia, 3.1 million; South and South-east Asia, 3.3 million; East-Asia and Pacific, 2.3 million). Estimates of HIV prevalence were available for 78 countries. HIV prevalence among IDU of over 20% was reported for at least one site in 25 countries and territories: Belarus, Estonia, Kazakhstan, Russia, Ukraine, Italy, Netherlands, Portugal, Serbia and Montenegro, Spain, Libya, India, Indonesia, Malaysia, Myanmar, Nepal, Thailand, Viet Nam, China, Argentina, Brazil, Uruguay, Puerto Rico, USA and Canada.
Conclusions: These findings update previous assessments of the number of countries with IDU and HIV-infected IDU, and the previous quantitative global estimates of the prevalence of IDU. However, gaps remain in the information and the strength of the evidence often was weak.
The United Nations General Assembly Special Session on HIV/AIDS ‘Declaration of Commitment on HIV/AIDS’ acknowledged that ‘by the end of 2000, 36.1 million people worldwide were living with HIV/AIDS, 90% in developing countries’ . Ten percent of the HIV/AIDS cases worldwide are attributed to injecting drug use (IDU) . It has been estimated that up to 10 million people worldwide inject drugs, and by the end of 1999 IDU had been reported by 136 countries and 114 have reported HIV infections associated with IDU . The importance of IDU in different regions in contributing to HIV epidemics is well documented [3,4].
In addition to the classification of HIV epidemic scenarios (low-level, concentrated and generalized) , which defines the current status of the epidemic in a given territory, several situations can be identified according to both the dimension of the epidemic and its prevalent routes of transmission. Thus, sub-Saharan Africa contains 70% of the HIV/AIDS cases (over 26 million people living with HIV/AIDS) with heterosexual transmission as the main route . However, China, Indonesia, Viet Nam, several Asian republics, the Baltic States and North Africa have HIV epidemics driven by unsafe drug-injecting practices with additional HIV spread occurring through commercial sex work . Furthermore, it has been recently estimated that in many countries in Europe, Asia, the Middle East and the Southern cone of Latin America, the sharing of injecting equipment is the primary mode of transmission, accounting for 30–90% of all reported infections .
Estimates of the prevalence of IDU and related HIV infection are critical to planning intervention responses, and to measuring the coverage of harm reduction (e.g. needle exchange/distribution, substitution treatment) and provision of anti-retroviral treatment (ARV) for IDU. However, information on the number of IDU or the prevalence of HIV infection among them is still scarce in key countries . In 2001, the UN Reference Group on HIV/AIDS Prevention and Care among IDU in Developing and Transitional Countries was established to advise UNAIDS and co-sponsors on relevant issues regarding the HIV epidemic among IDU in developing and transitional countries. The group seeks to enhance an evidence-based approach to HIV prevention and care among IDU. Among its mandates is to synthesize and disseminate evidence on international HIV epidemiology, surveillance and HIV prevention and care among IDU. In this paper we report progress towards obtaining global, regional and national estimates of the prevalence of IDU, and prevalence of HIV infection among IDU.