It is dangerous to believe that the end of AIDS is in sight.
Around 30 million people around the world live with HIV, and another 30 million could become infected in the next decade if current trends persist.
Billions of dollars have been spent on well-meaning attempts to save lives, with an alarming lack of high-quality evaluation of how these investments have performed.
This is true not only of abstinence campaigns, for which there is no evidence of effectiveness, but also for many other mainstays of the AIDS response.
We do not know what works, where, and why, or how to replicate our successes.
For the project RethinkHIV, the Copenhagen Consensus Center and the Rush Foundation asked 30 of the world's top HIV economists, supported by epidemiologists, demographers, and medical professionals, to analyze the most promising responses to the epidemic in the world's worst-hit region, sub-Saharan Africa.
They were asked to examine what could be achieved with extra investments in six key areas: prevention of sexual transmission, reduction of non-sexual transmission, treatment of AIDS patients, initiatives to use social policy and health-system strengthening to fight HIV/AIDS, and vaccine research.
Based on this research, the Co-penhagen Consensus Center and the Rush Foundation then asked five world-class economists including three Nobel laureates to form their own conclusions about how best to spend additional funding.
The panel zeroed in on five investments that they believe should be at the top of policymakers' lists.
Most importantly, they identified an urgent need for increased investment in developing an HIV vaccine.
This is clearly a longer-term response to the epidemic. Research by Dean Jamison and Robert Hecht suggests that we are about 20 years away from large-scale vaccination, and that increasing current funding by around 10 per cent, or $100 million (S$127 million) a year, would meaningfully shorten that projection.
This would save millions of lives and potentially end the epidemic in the long run.
For every dollar spent, it is likely that the benefits would run into the tens of dollars.
As a shorter-term response, the Nobel laureates were convinced by research by the economist Lori Bollinger that we could practically wipe out mother-to-child transmission of HIV by 2015 with additional expenditures of just $140 million a year.
About 350,000 infants became HIV positive in 2008, through pregnancy, labor, delivery, or breastfeeding, accounting for approximately 20 per cent of all new infections.
They also concluded that spending more to make blood transfusions safer would be worthwhile.
Bollinger calculated that an annual investment of $2 million over five years would achieve 100 per cent safe blood transfusions by 2015 and avert more than 131,000 HIV infections, while alleviating fears of infection for people who would otherwise receive blood that was not comprehensively screened.
The Nobel laureates also found that male circumcision is an excellent use of funds.
They focused particularly on the longer-term benefits of infant-male circumcision, arguing that there is massive untapped potential to introduce this very cheap practice across Africa.
We know that adult-male circumcision reduces the odds of transmission from a woman to a man by up to 60 per cent.
Research by Jere Behrman and Hans-Peter Kohler of the University of Pennsylvania makes clear that the real focus needs to be on working out the best ways to broaden adult circumcision efforts across the region, and to convince men that getting circumcised is a good idea.
We also need to introduce counseling to ensure that men do not treat circumcision as a vaccine, and engage in riskier behavior as a result.
Finally, the panel of Nobel laureates concluded, based on research by Mead Over and Geoffrey Garnett, that additional resources for treatment should go first to patients who are the sickest and most infectious.
Because treatment is very expensive, coverage rates remain woefully inadequate. But treatment is not only an ethical imperative; it is also important in preventing and reducing sexual transmission.
The expert panel also highlighted promising areas where more research is needed. As Anna Vassall, Michelle Remme, and Charlotte Watts of the London School of Hygiene and Tropical Medicine pointed out, gender inequalities and domestic violence are both associated with a significant increase in risk of HIV infection.
So, if gender-training programs were to piggyback on current income-boosting microfinance and agricultural-support programs, we could undermine norms about gender roles that entrench women's dependence on men or condone domestic violence.
We need to arrest the recent decline in AIDS funding and secure additional resources in order to make further headway against the deadly disease.
The author is head of the Copenhagen Consensus Center, and adjunct professor at Copenhagen Business School.