Continuing expansion of the HIV/AIDS pandemic has been recognised as an exceptional challenge to global health, international development, and world security. UNAIDS estimates that there were more than 38 million people living with HIV at the end of 2005, with just over 4 million new infections that year. 2 While most new cases continue to emerge from developing nations, even in developed countries HIV incidence remains unacceptably high. 3 The high incidence is not likely to change in the foreseeable future because:(1) HIV-prevention strategies are only partly effective and remain severely underused; 4–10 (2) a preventive vaccine remains elusive; 11 and (3) current treatment strategies cannot eradicate HIV infection. 12–15 Nowadays, the exceptional threat to humanity that the HIV pandemic represents, and the similarly exceptional interventions that will be needed to stem the relentless global growth of AIDS deaths and new HIV infections, is widely recognised. 1, 16, 17

Highly active antiretroviral therapy (HAART), first introduced in 1996, 18–20 substantially reduced AIDS-related hospital admissions and death rates in both developed and developing nations. 21–23 Despite these encouraging results, the early optimism generated by HAART was tempered by regimen complexities, adverse effects, toxicities, and cost. 24, 25 In the past decade, HAART regimens have become markedly simpler, better tolerated, less toxic, and more effective. 26–28 As a result, expansion of HAART programmes in developing nations has become a welcome reality. 29 Although concerns have been expressed with regard to the potential negative effects of suboptimal adherence leading to HIV-drug resistance in settings where scale-up of HAART is taking place, recent data suggest that good adherence can be attained in resource-limited settings and in marginalised populations in developed nations. 30, 31