Evidence of associations between socioeconomic status and the spread of HIV in different settings and at various stages of the epidemic is still rudimentary. Few existing studies are able to track incidence and to control effectively for potentially confounding factors. This paper reviews the findings of recent studies, including several included in this volume, in an attempt to uncover the degree to which, and the pathways through which, wealth or poverty is driving transmission in sub-Saharan Africa. We investigate the question of whether the epidemic is transitioning from an early phase in which wealth was a primary driver, to one in which poverty is increasingly implicated. The paper concludes by demonstrating the complexity and context-specificity of associations and the critical influence of certain contextual factors such as location, gender and age asymmetries, the mobility of individuals, and the social ecology of HIV transmission. Whereas it is true that poor individuals and households are likely to be hit harder by the downstream impacts of AIDS, their chances of being exposed to HIV in the first place are not necessarily greater than wealthier individuals or households. What is clear is that approaches to HIV prevention need to cut across all socioeconomic strata of society and they need to be tailored to the specific drivers of transmission within different groups, with particular attention to the vulnerabilities faced by youth and women, and to the dynamic and contextual nature of the relationship between socioeconomic status and HIV.

In sub-Saharan Africa, HIV prevalence does not exhibit the same pattern of association with poverty as most other diseases. HIV programmes should also focus on the wealthier segments of the population.

The authors discuss the "downstream" effects of AIDS on poverty, and the "upstream" effects of poverty upon acquiring HIV.

Objectives To review the literature on the potential efficiency gains of integrating HIV services with other health services. Design Systematic literature review. Search of electronic databases, manual searching and snowball sampling. Studies that presented results on cost, efficiency or cost-effectiveness of integrated HIV services were included, focusing on low-and middleincome countries. Evidence was analysed and synthesised through a narrative approach and the quality of studies assessed. Results Of 666 citations retrieved, 46 were included (35 peer reviewed and 11 from grey literature).

A strong, global commitment to expanded prevention programs targeted at sexual transmission and transmission among injecting drug users, started now, could avert 28 million new HIV infections between 2005 and 2015. This figure is more than half of the new infections that might otherwise occur during that period in 125 low- and middle-income countries. Although preventing these new infections would require investing about U.S.$122 billion over this period, it would reduce future needs for treatment and care. Our analysis suggests that it will cost about U.S.$3900 to prevent each new infection, but that this will produce a savings of U.S.$4700 in forgone treatment and care costs. Thus, greater spending on prevention now would not only prevent more than half the new infections that would occur from 2005 to 2015 but would actually produce a net financial saving as future costs for treatment and care are averted.