The revised figures, from 39.5 million down to 33 million, reflect a significant adjustment of estimates from India, where improved statistical techniques have yielded new results.
In 2007, 33.2 million people were living with HIV, 2.5 million people became newly infected and 2.1 million people died of AIDS.
Although the overall prevalence of HIV has remained "relatively constant for several years," according to Peter Ghys who heads the epidemiology and analysis division of UNAIDS, there was hopeful news, particularly in sub-Saharan Africa, where the younger generation is reporting fewer new cases than their predecessors are. They are "reporting [fewer] sexual partners and also reporting increased condom use," Ghys says.
Still, approximately 22.5 million people in sub-Saharan Africa live with the disease, and it continues to be the number one killer in the region.
Each day, there are more than 6,800 new HIV infections reported worldwide, and 5,700 AIDS-related deaths.
"This is an epidemic where we need eternal vigilance and to never let our guard down," UNAIDS director of evidence, monitoring and policy Paul De Lay said, pointing to increased infection rates in countries like the United States.
"If we start to neglect our prevention programs, the epidemic turns around and starts to increase again," he added.
