"The number of people becoming infected and dying is decreasing, but the international resources needed to sustain this progress have declined for the first time in 10 years, despite tremendous unmet needs," UN Secretary General Ban Ki-moon warned on Friday.
"We have a long way to go to prevent new HIV infections, end discrimination and scale up treatment, care and support," he said in a foreword to the report.
The 139-page document, "AIDS at 30: Nations at the Crossroads," coincides with the anniversary on June 5 of a 1981 report by US epidemiologists describing the case of five young homosexuals whose immune systems had been destroyed.
|The UN Secretary-General, Ban Ki-moon (R) speaks next to UNAIDS Executive Director Michel Sidibe during a press conference on March 31, in Nairobi|
That condition, later named acquired immune deficiency syndrome, has since killed nearly 30 million people, and more than 33 million others have the human immunodeficiency virus (HIV) that causes it, according to UNAIDS estimates.
The UN General Assembly in New York will hold a high-level meeting from June 8-10 to assess progress in the campaign.
UNAIDS painted a tableau of early setbacks and later successes in the fight against a complex disease.
It hailed in particular "dramatic gains" in getting AIDS drugs -- once the preserve of rich economies -- to patients in poor countries.
At the end of 2010, 6.6 million people in low- and middle-income countries had access to treatment, it said.
This amounted to an increase of 1.4 million over 2009, and a 22-fold rise over 2001, "a vivid illustration of the power of international solidarity, innovative approaches and people-centred responses."
On the downside, the global tally still fell far short of the goal of "universal access" that the United Nations had enshrined for 2010. That deadline came and went with another nine million badly-infected people still in need of treatment.
Achieving that aim and tackling the many other issues of AIDS will require a major boost in funds, UNAIDS warned.
Between 2001 and 2009, resources for poorer countries rose 10-fold, from 1.6 billion dollars annually to 15.9 billion.
But this rise masks a flatlining that began with the 2008 financial crisis as western countries that are overwhelmingly the biggest foreign contributors began to tighten their belts.
The United States alone accounted for 3.165 billion dollars in AIDS support in 2009, followed by Britain, with 658 million and the Netherlands with 389 million dollars, although Denmark donated most as a percentage of its GDP.
"Waning support" had to be reversed, said the report.
Without naming names, it urged middle-income countries to entirely self-finance their AIDS programmes within the next few years.
And in a veiled reference to China and other developing giants, it said "some countries that are now emerging as global and regional economic powers may in due course" become donors rather than recipients.
Donations from China and oil-rich Gulf nations have become a sticky issue in the field of AIDS. Sources say Michel Kazatchkine, head of the Global Fund to Fight AIDS, Tuberculosis and Malaria, has worked hard to drum up help from these countries but so far to little effect.
The report also pointed the finger at countries that were doing too little to prevent new infections, or failing to spend money in ways that would have the greatest impact.
In West Africa, scarce funds for prevention programmes often bypassed sex workers or gays, whose HIV prevalence was 10 times greater than in the rest of the population.
In parts of southern Africa, older heterosexuals account for a big chunk of new infections, but there are few programmes specifically designed to convey a safe sex message to them.
And in Asia, meanwhile, some 90 of spending on prevention for young people fails to target the youngsters who are at higher risk of infection.
Veteran AIDS campaigner and former US president Bill Clinton said the fight against AIDS had to adjust to leaner times by being smarter and less wasteful.
NGOs had to cut their overheads, governments had to reduce costs and efforts had to be focused on population niches most at risk of infection.
"By doing these things, even with the same level of funding, we can prevent many more infections," Clinton said.