Reduction In HIV-1 Incidence Among Rural Ugandans Gives Hope To Other African Countries

A study in this week’s issue of THE LANCET highlights a reduction in both HIV-1 incidence (the number of new cases) and prevalence (the number of cases in the population) from the beginning to the end of the past decade among a rural Ugandan population. Authors of the study conclude that the results could offer hope for other sub-Saharan countries where the HIV-1 infection rate remains high.

HIV-1 incidence rates in a community are a more accurate measure of epidemic trends than prevalence rates from surveillance, as they are not influenced by death rates, migration, or survey coverage. In Uganda, there have been encouraging reports of reductions in HIV-1 prevalence, but no reliable data exist for trends in incidence.

James Whitworth from the Medical Research Council Programme on AIDS in Uganda, and colleagues surveyed the adult population of 15 neighbouring villages for HIV-1 infection using annual censuses, questionnaires, and serological surveys.

HIV-1 incidence fell from 8.0 to 5.2 per 1000 person years at risk between 1990 and 1999. Incidence was 37% lower in the second half than the first half of the decade. HIV-1 prevalence fell significantly between the first and tenth annual survey rounds, especially among men aged 20–24 years (6.5% to 2.2%) and 25–29 years (15.2% to 10.9%). There were also substantial reductions in HIV-1 prevalence rates among women aged 13–19 years (2.8% to 0.9%) and 20–24 years (19.3% to 10.1%)

James Whitworth comments: “More than half a million people have died from AIDS in Uganda since the start of the epidemic, which still rages at unacceptably high rates throughout sub-Saharan Africa. However, our findings strengthen evidence from earlier studies of declines in HIV-1 prevalence and increases in risk-lowering sexual behaviour, and gives hope that AIDS control programmes can control the AIDS epidemic with messages about changes in behaviour.”

In an accompanying Commentary (p 3), Andrew Grulich from National Centre in HIV Epidemiology and Clinical Research, Sydney, Australia, concludes: “It is now clear that there has been a measure of success, as indicated by declining HIV risk behaviours, prevalence, and probably incidence, in a few sub-Saharan countries. This should be seen as encouraging evidence that well-supported social and behavioural prevention works, and that sentinel surveillance, carefully interpreted, can provide information of the success or otherwise of intervention programmes. Nevertheless, ongoing high rates of HIV transmission across sub-Saharan Africa, even in the more successful countries such as Uganda, and in high-risk populations elsewhere, means that simple, affordable, and effective biomedical means of HIV prevention are desperately needed.”

In a Viewpoint article (p 78), Justin Parkhurst from the London School of Hygiene and Tropical Medicine, UK, acknowledges the success of Uganda in slowing the prevalence of HIV/AIDS, but cautions against the use of exaggerated claims and the oversimplification of the Ugandan model. He concludes: “The use of selective evidence as the basis for policy recommendations can be misleading and counterproductive. Countries with HIV-1 prevalence rates of more than 30% (such as some in Southern Africa) would be wrong to assume that by simply copying a few obvious Ugandan government interventions, they can expect to see a two-thirds reduction in their HIV-1 prevalence rate. Although Uganda has indeed done much in its struggle against HIV/AIDS, and the Ugandan experience can provide valuable information to assist other nations in their prevention efforts, inappropriate recommendations based on poor interpretation of evidence must not be used as the basis for policy.”