The United Nations has slashed its estimates of how many people are infected with the AIDS virus, from nearly 40 million to 33 million.

In a report to be issued on Tuesday, the U.N. says revised estimates on HIV in India account for a large part of the decrease.

The agency admitted it overestimated how many people are infected with the incurable virus, and said better methods of collecting data show it is not quite as common as feared.

The single biggest reason for this reduction was the intensive exercise to assess India's HIV epidemic, which resulted in a major revision of that country's estimates, the report said.

After originally estimating some 5.7 million people were infected in India, the U.N. more than halved that estimate, to 2.5 million.

But the numbers nonetheless show the epidemic is overwhelming and that efforts to fight HIV must still be stepped up, said officials at the U.N. AIDS agency UNAIDS.

These improved data present us with a clearer picture of the AIDS epidemic, one that reveals both challenges and opportunities, UNAIDS Executive Director Dr. Peter Piot said in a statement.

Unquestionably, we are beginning to see a return on investment -- new HIV infections and mortality are declining and the prevalence of HIV leveling. But with more than 6,800 new infections and over 5,700 deaths each day due to AIDS, we must expand our efforts in order to significantly reduce the impact of AIDS worldwide.

The new numbers suggest that some 33.2 million people are infected with the human immunodeficiency virus -- about 30.8 million adults and 2.5 million children.


UNAIDS estimated that 1.7 million people became newly infected in sub-Saharan Africa this year, a significant reduction since 2001.

But Africa remains by far the continent hardest hit by AIDS, with 22.5 million people infected with HIV.

Eight countries in this region now account for almost one-third of all new HIV infections and AIDS deaths globally, said UNAIDS.

In Asia, the estimated number of people living with HIV in Vietnam has more than doubled between 2000 and 2005 and Indonesia has the fastest growing epidemic.

The report gives two reasons for the downward revisions -- one is better data and the other is an actual decrease in the number of new infections.

UNAIDS and (the World Health Organization) are now working with better information from many more countries, UNAIDS said.

The number of new HIV infections each year likely peaked in the late 1990s at 3 million and was estimated at 2.5 million for 2007, UNAIDS said.

This reflects natural trends in the epidemic, as well as the result of HIV prevention efforts. Of the total difference in the estimates published in 2006 and 2007, 70 percent are due to changes in six countries: Angola, India, Kenya, Mozambique, Nigeria, and Zimbabwe, the report said.

In both Kenya and Zimbabwe, there is increasing evidence that a proportion of the declines is due to a reduction of the number of new infections which is, in part due to a reduction in risky behaviors.

The U.N also changed its estimate on how long it takes to die of AIDS if not treated from 9 years to 11 years.