RESUMEN
Immense progress has been made in the fight against HIV and AIDS. Achieving and exceeding the AIDS targets for the Millennium Development Goals (MDGs) was accomplished; in large part; due to an unprecedented financial investment from the international community. Following an $800 million dip in donor disbursements in 2010; the discourse has since shifted to the need for greater sustainability of funding. But what does sustainability mean? Current efforts focus heavily on fiscal imperatives such as increasing domestic funding. This is important - needs are increasing at a faster rate than donor funding; especially with increased treatment coverage. The problem is that measures of financial sustainability tell very little about the actual sustainability of specific programmes; disease trajectories or enabling environments. Recognising that current definitions of sustainability lack clarity and depth; we offer a new six-tenet conceptualisation of what sustainability means in the HIV and AIDS response: (1) financial; (2) epidemiological; (3) political; (4) structural; (5) programmatic; and (6) human rights. Based on these; we examine examples of donor transitions for their approach to sustainability; including PEPFAR in South Africa; the Global Fund in Eastern Europe; and the Bill and Melinda Gates Foundation in India (Avahan). We conclude that sustainability must be understood within a broader framework beyond funding stability. We also recommend that certain interventions; such as programming for key populations; may have to continue to receive external support even if affected countries can afford to pay