The number of people living with HIV is at its highest yet, a report shows.
The UNAids report details the incidence of HIV/Aids around the world
UNAids says there are an estimated 40.3m people currently living with the virus across the world, with almost 5m infected in 2005.
And it warns there are growing epidemics in Eastern Europe and Central and East Asia.
But the report says falls in HIV incidence have been seen in certain groups, including sex workers and their clients in Thailand and Cambodia.
Other groups in which education and prevention efforts have helped reduce HIV infection rates are young people in Uganda, injecting drug users in Spain and Brazil and men who have sex with men, across Western countries.
Overall, the report says more than 3m people died of Aids-related illnesses in 2005. Of these, more than 500,000 were children.
The report says Sub-Saharan Africa is still hardest hit by HIV/Aids.
Two thirds of the people living with HIV - 25.8m - are in this area.
In 2005, 2.4m people in Sub-Saharan Africa died of an HIV-related illness, and a further 3.2m were infected with the virus.
The report says access to antiretroviral treatments for HIV have improved dramatically, with many more people across the world able to access the drugs.
It says: "It is no longer only in the wealthy countries of North America and Western Europe that persons in need of treatment have a reasonable chance of receiving it.
"Treatment coverage in countries such as Argentina, Brazil, Chile and Cuba now exceeds 80%."
But UNAids says the situation is still difficult for people in the poorest countries of the world.
"At best, one in 10 Africans and one in seven Asians in need of anti-retroviral treatment were receiving it in mid-2005.
Dr Peter Piot, UNAids executive director, said: "The reality is that the Aids epidemic continues to outstrip global and national efforts to contain it.
"It is clear that a rapid increase in the scale and scope of HIV prevention programmes is urgently needed.
"We must move from small projects with short-term horizons to long-term, comprehensive strategies."
Nick Partridge, Chief Executive of Terrence Higgins Trust said: "We're still not containing the HIV epidemic.
"The downturn in new infections in some communities shows we can win this fight but we need resources, public pressure and political action."
He added: "We need to do more to see figures decrease around the world.
"At home we need greater investment in safer sex campaigns for gay men and African people.
"This report reminds us yet again that these campaigns really work."
More funds needed
Anton Kerr, of Christian Aid, called on governments to contribute more to the Global Fund for HIV/Aids, TB and Malaria.
A Global Fund replenishment conference in September heard that double the £2.1bn donated to that point was needed to fund new prevention, treatment and care programmes in 2006 and 2007.
Mr Kerr said: "Millions of people are relying on the promises made by the most powerful and rich countries in the world.
"However, the scandal of their failure to fully fund the Global Fund shows that they are not acting quickly enough to save the lives they have committed to saving. Empty promises mean death sentences."
Yusef Azad, of the National Aids Trust said many people were dying unnecessarily.
"Fewer than a fifth of those at risk of HIV have access even to the most basic prevention services; only one in ten of those living with HIV have been tested and know they are infected and only 15% of those who need life-saving HIV drugs in low and middle-income countries actually receive them.
"What is needed is the political will to end this global health injustice and a determination to roll out what works rather than be tempted by dogma or prejudice."