Over the past decade, there has been a dramatic expansion of services in developing countries to prevent and treat human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), with substantial support from global health initiatives. During 2000–2008, overall spending on HIV infection and AIDS in low- and middle-income countries increased approximately 10-fold, to US$ 13.7 billion.1 Rapid and comprehensive responses to the HIV pandemic have substantially improved the health and social well-being of populations in various settings. For example, in the region denoted by the United Nations as Asia and the Pacific, where the burden of HIV infection is second only to that in Africa, there was an average 20% decline in new infections annually during 2001–2009.2 In addition, widespread scale-up of antiretroviral therapy (ART) has encouraged HIV testing and early access to health-care services and has improved health status and quality of life among people living with HIV infection.3,4 HIV transmission in this region is driven primarily by three high-risk behaviours: unprotected sex between males and female commercial sex workers, injection opioid use (hereafter, “injection drugs”) and unprotected sex between males. Governments can halt and reverse the HIV epidemic and save money if they achieve universal coverage of comprehensive interventions among these high-risk populations.4