The Joint United Nations' Programme on HIV/AIDS (UNAIDS) annual report shows that the global HIV epidemic is either slightly stabilising or decreasing. The stabilising epidemic has also been noted in South Africa which has the world's largest HIV epidemic with 5.7 million infections.

Sub-Saharan Africa still accounts for the greatest portion of the world's burden of disease. Two-thirds of those living with HIV are from this region and three-quarters of those who died of AIDS-related illnesses last year also lived in sub-Saharan Africa. But what does it actually mean to say that the epidemic is stabilising?

"Here, in southern Africa, what we have experienced is rapid increases in prevalence rates and now a stabilisation for about the last four or five years. But that stabilisation is basically driven by the number of new infections being matched by the number of deaths due to AIDS... There is no reduction in the rates of HIV infection. That's what we're seeing. We're seeing a pretty constant rate of HIV infection, but in terms of the prevalence rate it's being offset by the rate of deaths due to AIDS. What we want to see is a reduction in the rate of new infections", explained Mark Stirling, the Regional Director of UNAIDS's support team in east and southern Africa.

UNAIDS's report notes that Southern Africa continues to be the epicentre of the epidemic throughout the continent. More than 30% HIV infections and AIDS-related deaths last year occurred in the sub-region. However, stabilisation of the epidemic has been noted in three countries - Malawi, Zambia and South Africa. But South Africa still has the largest population of people with HIV in the world, an estimated 5.7 million people.

"The stabilisation of prevalence rates is across the full age range, 15 - 49. What we're seeing if you break down prevalence rates is very, very low levels of HIV infection amongst young girls and boys until the age of about 14, 15. And then an extremely rapid increase in rates of HIV infection, particularly amongst girls from 15 - 24 years, and that's going from round about 2% to round about 20, 25%. And that is a six-fold greater number of infections than amongst young boys. But then as we move on from around about 25, these rates of infections amongst boys and girls, men and women sort of equalise", said Stirling describing the nature of South Africa's epidemic.

He added that "we have no reason to claim comfort in the success of prevention efforts through stabilisation of the epidemic".

However, a few countries have shown a slight reduction in new infections over the last decade. In southern Africa these are Zimbabwe and Botswana, while in east Africa they are Uganda, Kenya and parts of Tanzania.

This report, unveiled just before the 17th International AIDS Conference to be held in Mexico starting this Sunday, should give food for thought to delegates on how to improve prevention campaigns - the only way to reduce HIV infection levels in the absence of a successful scientific intervention.