|Michel Sidibe warned that despite the progress, it is too early to say 'mission accomplished' [GALLO/GETTY]
The number of new cases of HIV/Aids has dropped by about one-fifth over the past decade, although millions of people still lack access to new methods of prevention and treatment.
In 2009, 2.6 million people contracted the HIV virus that causes Aids, down 19 per cent from the 3.1 million recorded in 2001, UNAids, the United Nation's agency spearheading the campaign, announced on Tuesday.
While positive about the growing impact prevention measures and treatment are having on the Aids epidemic, the UNAids' 2010 global report on the Aids epidemic also highlighted the dangers of backslide.
"Fifty-six nations around the world have stabilised or significantly reduced infections," Michel Sidibe, the executive director of UNAids, said.
"We have halted and begun to reverse the epidemic. Fewer people are becoming infected with HIV and fewer people are dying from Aids.
"However we are not yet in a position to say 'mission accomplished'."
The report showed that treatment has made huge inroads in the past five years.
About 5.2 million people in poor countries had access to costly lifesaving antiretroviral medicine in poor countries last year, compared to 700,000 in 2004.
33.3 million people worldwide were living with HIV in 2009
In eastern Europe and central Asia, the number of people with the virus has almost tripled over the past decade
Around 10 million people who need antiretrovirals do not have them
Aids-related deaths in sub-Saharan Africafell by 20 percent over the past five years
The annual death toll in Asia has grown to 300,000
However, overall "demand is outstripping supply," Sidibe warned.
And this trend could continue - investment against HIV/Aids stopped growing for the first time last year.
"If we stop financing, the five million people who are under treatment will start to die," he warned.
An estimated 10 million people who need antiretrovirals do not have them, while "stigma, discrimination, and bad laws continue to place roadblocks for people living with HIV and people on the margins" of society, he said.
The report found that epidemics in sub-Saharan Africa, the worst hit region, were declining or stable.
Aids-related deaths there fell by 20 per cent over the past five years, while the number of people living with the HIV declined from an estimated 2.2 million to 1.8 million.
In South Africa, which has more people than any other country with the virus that causes Aids, the report says new infections have reduced by more than 25 per cent in the same time period.
Sheila Tlou, UNAids regional director for sub-Saharan Africa, says the drop in Africa is because of increased condom use, abstinence and improved awareness of AIDS.
"The efforts of anti-retroviral therapy are really evident, especially in our region of the world, sub-Saharan Africa, where because of access we have seen 20 per cent fewer deaths related to HIV than in 2004," she said.
Yet across sub-Saharan Africa, 22.5 million people are still living with HIV, more than any other region in the world, and 68 per cent of the global total of 33.3 million people, UNAids found.
In Asia, HIV stabilised at a caseload of about 4.9 million, with "significant" progress on tackling mother-to-child transmission, when pregnant women pass on the virus to their babies, UNAids said.
In India, Nepal and Thailand the rate of new infections fell by more than one-quarter.
However, the annual death toll has grown by about 50,000 to 300,000 in Asia over a decade. The pattern of disease within highly populated countries such as China and Indonesia can vary significantly.
The biggest inroads were found in North America and west and central Europe, with a 30 per cent decline in the caseload over a decade.
But new infections rose there slightly last year and UNAidsS signalled a resurgence of the epidemic among male homosexuals due to unprotected sex.
In eastern Europe and central Asia, the number of people with the virus has almost tripled over the past decade to reach about 1.4 million, while deaths grew fourfold.
Russia and Ukraine account for nearly 90 per cent of new infections in the region.
In news that promises to reinforce the wider "prevention revolution" heralded by Sidibe, a daily dose of an oral antiretroviral drug reduced the number of HIV infections among sexually active gay men by 44 per cent, in what scientists claimed on Tuesday is the latest breakthrough in the fight to further stem the virus's spread.
The study of the pill Truvada was conducted by the US Centres for Disease Control and Prevention (CDP) and involved 2,500 gay and bisexual men, and 29 transgender women.
Participants between the ages of 18 and 67 were drawn from six countries, including Brazil, Ecuador, Peru, South Africa, Thailand and the US.
Its authors urge people to wait for guidelines on how to use the drug safely and effectively. Condoms and safe sex remain the best ways to prevent Aids transmission, they warned.
The results will be published in the November 25 issue of the New England Journal of Medicine.
The study follows the ground-breaking results earlier this year for a microbicide gel that could help women protect themselves.
All participants in the CDP trials were given counselling on preventing the spread of the virus as well as condoms and medical care for other sexually-transmitted diseases during the course of the study.
The US National Institute of Allergy and Infectious Diseases sponsored much of the study, with additional funds provided by the Bill and Melinda Gates Foundation.
California-based Gilead Sciences, which makes Truvada, donated the drugs used.
Gay men are one of the most at-risk groups for HIV in the United States, accounting for more than half of the 56,000 new infections each year. One in five gay men living in 21 major US cities is infected with HIV and nearly half are unaware of it, according to a separate study by the CDP that was published in September.