The interpretation of HIV prevalence trends in South Africa is increasingly complex as the epidemic matures and prevention, care and treatment efforts are implemented. Increased access to antiretroviral treatment (ART) has increased the survival time of people living with HIV (Jahn et al. 2008) and, as a consequence, HIV prevalence is likely to increase predominantly in the older age groups who are more likely to be in need of receiving ART. Successful prevention programmes, on the other hand, may have contributed to a reduction in new infections, that is, HIV incidence.

Increasing coverage of ART programming in conjunction with reduction in new infections may have the potential effect of maintaining prevalence at the same level, thus making it difficult to draw conclusions about the epidemic over time using prevalence as the only measure. This should be borne in mind when interpreting the present findings on HIV prevalence.

The 2002, 2005, and 2008 surveys are comparable for the population aged 2+ years and similar prevalence levels were found in all three studies. HIV prevalence in the total population of South Africa has stabilised at a level of around 11%.

A decline in HIV prevalence at national level has been observed among children aged 2-14, from 5.6% in 2002 to 2.5% in 2008. This drop could probably be attributed to programmes that address the issue of mother-to-child transmission. There was a slight decrease of HIV prevalence among youth 15-24, from 10.3% in 2005 to 8.6% in 2008. Such a decrease is probably attributable to the significant increase in condom use observed among males and females within this age group. Also, the fact that HIV communication programmes have been shown to reach a large population within this age group may have played a role in terms of HIV education.

HIV prevalence remains disproportionately high for females in comparison to males, and peaks in the 25-29 year age group, where one in three (32.7%) were found to be HIV positive in 2008. This proportion has remained unchanged since 2002, and was at the same level in all three surveys. The sustained high levels of HIV infection among young females is one of the most concerning findings of the 2008 survey and needs urgent attention for effective HIV prevention among females in their prime child-bearing age.

HIV prevalence levels in the age group 15-49 years slightly increased from 15.6% in 2002 to 16.2% in 2005 and 16.9% in 2008. The increase in HIV prevalence was predominantly observed among females 30+ years. As discussed above, the interpretation of HIV prevalence trends in this age group is difficult without an in-depth analysis of HIV incidence and the impact of increasing access to ART.

Our efforts to monitor and respond to the South African HIV/AIDS epidemic are still complicated by the temporal and geographical evolution of the many sub-epidemics at the provincial or even sub-district level. Not surprisingly, HIV infection levels showed a very uneven distribution among the nine provinces. HIV prevalence increased in two provinces: in KwaZulu-Natal, HIV prevalence was 11.7% in 2002 and 15.8% in 2008 (a difference of 4.1%), and in Eastern Cape from 6.6% to 9.0% (a difference of 2.4%). Three provinces showed a proportional decline in HIV prevalence between 2005 and 2008 in the population aged 2+ years - Gauteng, Northern Cape, and Free State. However, the confidence intervals around the estimates indicate that the changes did not reach statistical significance.

The interpretation of epidemiological trends is made more difficult by an inadequate understanding of how different social, behavioral and epidemiological factors influence the dynamics of the epidemic within different settings. The challenge for programme designers now lies in identifying the most effective ways to decrease HIV transmission by influencing these factors and to translate these findings into specific interventions in the field (Rehle et al. 2004).

This is an extract from the "South African National HIV Prevalence, Incidence, Behaviour and Communication Survey, 2008" published by the Human Sciences Research Council, June 9 2009. The full report can be found here - PDF.

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