New calculations forced the United Nations to
slash its estimate of the number of people living with Aids around the world to 33.2m, while still highlighting the
continued spread of the disease.
Unaids, the joint UN programme on HIV/Aids, said that as a result of alternative methods and fresh information, especially from India, it was reducing its 2006 figures from 39.5m to 32.7m infected people.
The move is an
embarrassment for the agency since many national, international and non-governmental organisations use the statistics in its
annual report as a reference point for studying Aids, developing policy and seeking increased funding to
tackle the epidemic.
Peter Piot, the head of Unaids, said: "This is a challenge in terms of communication but we are not producing data for
advocacy. We have always wanted the most accurate data. Internally, science comes first and communication afterwards."
The revised statistics suggest that - partly as a result of prevention programmes - the number of people newly infected with HIV around the world in 2007 continued its
decline since the start of the decade, to 2.5m.
However, while annual new infections have dropped since 2001 in sub-Saharan Africa and south and south-east Asia, they have increased in North America and have barely changed in western Europe.
With a steady rise in the number of people in the developing world receiving antiretroviral therapy to 2.5m in 2007, the number of deaths from Aids at 2.1m fell less than the number of new infections. The result was to increase the total number living with HIV to 33.2m, representing a
prevalence of 0.8 per cent worldwide.
"Aids remains a huge crisis," said Mr Piot. "We must intensify prevention efforts. For every person put on treatment, there are four newly infected. That is
unsustainable. Treatment still has a long way to go. And we need to constantly improve data collection."
One reason for the new estimates was fresh research showing that people infected with HIV who go untreated live longer than previously thought - for a median of 11 years instead of nine years as previously believed.
Michel Kazatchine, head of the Global Fund to Fight Aids, Tuberculosis and Malaria, the multilateral
funder of treatment and prevention programmes, said need still substantially
outstripped resources. He did not
alter his call for $12bn-$18bn in international support for 2008-10.
Aids lobbyists were also quick to call for continued efforts to fight the infection. Steve Cockburn, campaign co-ordinator of the Stop Aids Campaign, a coalition of more than 80 UK-based
NGOs, said: "The new figures should be a call for action, not
complacency. The scale of the
challenge ahead remains huge."