AIDS has killed more than 20 million people and another 40 million are living with HIV, UNAIDS and the World Health Organization said Nov. 28.
"AIDS has become the most devastating disease humankind has ever faced," the agencies said. "HIV/AIDS is now the leading cause of death in sub-Saharan Africa. Worldwide, it is the fourth-biggest killer."
In many nations, "AIDS threatens human welfare, developmental progress and social stability on an unprecedented scale."
The epidemic is growing fastest in Eastern Europe and central Asia while sub-Saharan Africa continues to have the greatest number of cases. Asia and the Pacific region have a brief window of opportunity to arrest spread of the virus, the agencies said.
In some African nations, life expectancy has dropped to less than 40 years and economies will shrink by over 20 percent as the virus wipes out professionals and skilled workers, leaving millions of orphaned children in its wake, the report said.
In rich countries, people have become lax about protecting themselves while having sex or using illegal drugs, the agencies stated.
The report appeared just in advance of "World AIDS Day," which occurs annually Dec. 1.