The joint United Nations Programme on AIDS (UNAIDS) has dramatically reduced its estimate of the number of people living with HIV around the world. According to the new statistics, there are now 33.2 million people living with HIV globally, down from the 39.5 million estimate made at the end of 2006.
Much of the reduction can be attributed to better surveillance techniques now being used in many countries, most notably India. Earlier this year, India reduced its HIV estimate by around 3 million people after numbers from a large household survey showed HIV prevalence was much lower than previous antenatal clinic and surveillance site data had suggested. This trend has been echoed in several other countries, and has led UNAIDS to adjust antenatal survey estimates downwards by an average factor of 0.8 for the 2007 report. Antenatal surveys are considered less accurate than more general population sampling, as many of the women that access antenatal clinics will be (by default) more sexually active than other members of the population, and at a higher risk of having HIV.
Not all of the reductions in the new report are attributable solely to technical changes however. Encouragingly, in countries such as Kenya, Zimbabwe and Côte d’Ivoire, HIV prevalence has dropped, a trend which country officials say is due to behaviour change and greater awareness of AIDS. In Sub-Saharan Africa as a whole, there were an estimated 1.7 million new HIV infections in 2007 – considerably fewer than in 2001, when comparatively accurate monitoring of HIV rates first began.
Deaths from AIDS have also fallen, with an estimated 2.1 million people dying in 2007, down from around 2.3 million in 2005.
“For the first time, we are seeing a decline in global AIDS deaths," said Dr. Kevin De Cock, director of the AIDS department at the World Health Organization.
He attributed this decline to better global access to antiretroviral drugs, as well as the fall in HIV prevalence now being seen in many African countries.
"These improved data present us with a clear picture of the AIDS epidemic," added UNAIDS Executive Director, Dr. Peter Piot. "Unquestionably, we are beginning to see a return on investment."
Not everyone believes that the current statistics are any more accurate than previous estimates however. The AIDS Healthcare Foundation in the USA is arguing that the uncertainty highlights fundemental problems in the world's approach to AIDS.
"These figures are rough numbers based upon extrapolations gleaned from unreliable data, since so few people are being tested," said Michael Weinstein, the AHF's president. "Let's stop guessing and make routine testing worldwide a priority."
If the numbers in the new report are accurate, it would imply that the overall numbers of people infected with HIV are still increasing - revised estimates showed there were 2.5 million new infections last year. But HIV incidence - the rate at which new infections occur - is going down, and UNAIDS now believe that it may have peaked in the late 1990s.
UNAIDS has urged for the new statistics not be taken as an excuse to become complacent, or cut funding for AIDS. Dr Dr. Paul De Lay, director of Evidence, Monitoring and Policy at the organisation said that even with the downward revisions, the US$ 40 billion per year recommended for a comprehensive response to AIDS by 2010 would only drop to US$ 38 billion.