More than half a trillion dollars have been spent on HIV/AIDS worldwide between 2000 and 2015, a comprehensive analysis of funding for the disease by the Lancet has revealed.

The study showed that the total health spending, disaggregated by source into government spending, out-of-pocket, prepaid private and development assistance for health was $562.6 billion over the 16-year period. While the annual spending peaked in 2013 with $49.7 billion, in 2015, $48.9 billion was provided for the care, treatment and prevention of the disease. Governments were the largest source of spending on HIV/AIDS in 2015, contributing $29.8 billion or 61 per cent of total spending on HIV/AIDS.

Conversely, prepaid private spending was the smallest, making up only $1.4 billion of the 2015 total. "This research is an important initial step toward global disease-specific resource tracking, which makes new, policy-relevant analyses possible, including understanding the drivers of health spending growth," said Christopher Murray, Director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington-Seattle.

"We are quantifying spending gaps and evaluating the impact of expenditures." Development assistance for health (DAH), funding from high-income nations to support health efforts in lower-income ones, made up 0.5 per cent of total health spending globally in 2015; DAH totalled 30 per cent of all HIV/AIDS spending in 2015.

"Reliance on development assistance to fight HIV/AIDS in high-prevalence countries leaves them susceptible to fluctuations in the external resources available for HIV/AIDS," said Joseph Dieleman, from the IHME. "Nations' HIV/AIDS programmes are at risk for gaps in support and unrealised investment opportunities." For the study, the team worked with a group of 256 researchers in 63 countries.