Controversy over new AIDS projections

AIDS experts have raised doubts about a new study suggesting South Africa's HIV/AIDS epidemic peaked in 2002 and was expected to level off as fewer new infections were reported. The study, published in the recent issue of the African Journal of AIDS Research, said that the epidemic in South Africa peaked last year with about 4.69 million people living with HIV/AIDS and had started to level off. It also noted that HIV incidence rates in the 15 to 49 age group had decreased "substantially" from 4.2 percent in 1997 to 1.7 percent in 2003. These projections were based on a new statistical model developed by Dr Olive Shisana, executive director of HIV/AIDS research at the Human Sciences Research Council (HSRC), and Thomas Rehle, an independent consultant in international health and disease control. The study used data from the Department of Health's national antenatal HIV prevalence survey and the 2002 Nelson Mandela/HSRC Study of HIV/AIDS, Dr Thomas Rehle told IRIN. "This is an updated scenario and the model is not based on out of the sky assumptions, but real data from the field," he said. The researchers attributed the decrease in HIV prevalence to changes in sexual behaviour following the introduction of HIV prevention programmes and "the impact of rising HIV/AIDS related mortality". But leading South African HIV/AIDS researcher Rob Dorrington, director of the Centre for Actuarial Research at the University of Cape Town, was sceptical about the findings. Earlier studies of South African's HIV/AIDS epidemic had projected much higher HIV prevalence and mortality rates. The Actuarial Society of South Africa's statistical model - ASSA 2000 - predicts that without major behavioural or medical changes, life expectancy is likely to fall to 41 years by 2009. By then it expects that 16 percent of the total population will be infected with HIV. A report by the US Census Bureau projected that as many as 37.9 percent of sexually active adult South Africans could be HIV-positive by 2010, when there could be as many as 900,000 AIDS-related deaths each year. According to Dorrington, the new model was based on "a lot of assumptions". Consequently, the study results were "simply derived as a direct result of the assumption of future prevalence", he told IRIN. AIDS experts have also questioned the use of data from the Nelson Mandela/HSRC study, as the findings had not been through a peer-review process. But Rehle called for researchers to "focus on the debate on the interpretation of the currently available research". "Although our projections of the future HIV/AIDS burden in South Africa are relatively moderate compared to the projections made by various other researchers, the projected morbidity and mortality due to HIV/AIDS underscore nonetheless the same conclusion: the importance of acting now to fight the epidemic with an increased commitment from all levels of society," the study concluded.