Professor Marie-Louise Newell (UCL Institute of Child Health), seconded to lead the Africa Centre for Health & Population Studies, writes:

A quarter-century after the discovery of HIV as the causative agent of AIDS, and despite much progress in understanding this virus and its associated epidemic, HIV infection remains a major concern in sub-Saharan Africa, and Southern Africa in particular. It is sobering to realise that there are more cases of HIV infection in KwaZulu Natal, South Africa, than in Botswana and Uganda combined, and the Africa Centre surveillance area bears the brunt of this epidemic.

Since mid-2004, there has been an enormous effort to roll-out antiretroviral treatment (ART) across sub-Saharan Africa, which has been described as the largest ever public-health experiment on the continent. While the short-term benefits for HIV-infected individuals are beyond doubt, there remains considerable uncertainty regarding the long term impact on sub-Saharan African populations, especially in terms of further spread of the infection. Rates of new infection remain high, despite the engagement with communities now possible with the availability of treatment, and new strategies are required to allow the roll-out of ART to be sustainable. In the absence of an HIV vaccine in the foreseeable future, prevention will rely on other biomedical and behavioural interventions to prevent both acquisition of infection and onward transmission.

Successful approaches need to involve a combination of interventions targeted at the individual, the household, the community and the culture in general. Designing and evaluating such interventions requires a detailed understanding and engagement with a high-risk population and a continual process to monitor progress. The Africa Centre (www.africacentre.com), after 10 years of description at the heart of South Africa’s HIV epidemic, is developing a deeper understanding of the community it works with, in the hope of leading the way in eliminating HIV transmission and acquisition. With the challenges of life in rural South Africa, achievements here are highly relevant for other parts of sub-Saharan Africa.

The work of the centre is largely funded by the Wellcome Trust, with funding also from NIH and EDCTP, among others. The key objectives of the Centre’s research activities are:

• to further improve understanding of HIV dynamics and the impact of ART roll-out at individual, household, clinic and community level
• to identify approaches to, and target groups for, intervention
• to evaluate interventions at individual, household and community level
• to implement and further evaluate HIV treatment and prevention programmes.

In addition to the surveillance system, the Centre is a partner of the local Department of Health in a large HIV treatment and care programme, which extends to beyond the surveillance area to the Hlabisa sub-district. For people living in the centre’s surveillance it is possible to link the clinical data with the socio-demographic data at an individual level, which provides a powerful tool in the evaluation of the programme.

The longitudinal data from the Centre’s population-based HIV testing, Africa Centre demographic information system (ACDIS) and geographical information system (GIS) will be used to better understand the causal pathways of HIV infection (both in terms of acquisition and transmission of infection) by identifying and quantifying important environmental, community, household and individual-level determinants of HIV incidence and prevalence in a rural South African population.

The local community is seen as being vital both to understanding the spread of the epidemic and to effective prevention efforts. We will continue to investigate the determinants of HIV incidence, including the effects of school dropout, violence (against women), condom usage, sexual debut, age mixing, and concurrency, and community-level incidence on HIV acquisition. In addition, we will study clustering of HIV incident cases around ’hot spots’ such as bars and gasoline stations. Finally, we will study the changes of HIV incidence over time and characterise high-incidence communities and individuals.

We aim to reduce transmission of HIV infection in the area through the development of appropriate interventions that target both acquisition of infection in currently HIV-negative people and onward transmission of infection in already infected people. We have started demographic and qualitative work with individuals and households to understand their behaviour changes following HIV infection and treatment.

Although at the Centre and elsewhere experience has accumulated involving women in research, much less is known about how to engage men in research and preventive interventions. The role of men in the health of the household is being explored in a specific qualitative project, and the feasibility of working with men in prevention trials will be explored in another project. In-depth analysis of the sexual behaviour data collected within ACDIS since 2000 will provide a basis to inform the development of an intervention.