POLICYFORUM S

everal decades into the AIDS pandemic, HIV transmission in most of the world remains firmly concentrated among sex workers, men who have sex with men (MSM), injecting drug users (IDUs), and their sex part-ners (1). In some parts of Africa, where over two-thirds of infections occur globally, HIV has expanded outside these high-risk groups, creating generalized, predominantly hetero-sexual epidemics. In nine southern African countries, more than 12 % of adults are in-fected with HIV. Such devastating epidemics have frequently been attributed to poverty, lim-ited health services, illiteracy, war, and gender inequity. Although these grave problems demand an effective response in their own right, they do not appear to be the immediate causes of generalized epidemics (2). Some assumptions that drive current HIV prevention strategies are unsupported by rig-orous evidence. The presumption, for exam-ple, that poverty increases vulnerability to HIV infection is challenged by studies such as an analysis of recent Demographic and Health Surveys (DHSs) from Africa, which shows a strong positive correlation between HIV prevalence and wealth in eight countries examined (3, 4) [see supporting online mate-rial (SOM)]. Among Kenyan women, HIV prevalence is 3.9 % in the lowest economic quintile and 12 % in the highest. A study of serodiscordant couples found that, across 12 African nations, the woman was the HIV-infected partner in 34 to 62 % of these couples, which suggests that many infections are not, as is commonly assumed, brought into the relationship by the man (4, 5). African regions suffering from conflict, genocide, and rape, such as Rwanda, Congo, and Angola, are much less affected by AIDS than peaceful, wealthier, and more literate countries such as Botswana or Swaziland, which have the world’s highest HIV prevalence (6). Where multiple sexual partnerships, espe-cially concurrent ones, are uncommon, and particularly where male circumcision (MC) is common, HIV infec-tion has remained con-centrated in high-risk populations (7). Niger, a Muslim country where sexual behavior is re-latively constrained and MC is universal, has an adult HIV preval-ence of 0.7 % (1), de-spite being the lowest ranking country in th