Background: The spread of heterosexual HIV in developing countries is heterogeneous. Factors that explain the wide diversity of HIV prevalences in different countries are undetermined. International aid organizations currently appear to be focusing activities mainly on women rather than on men.
Goal: To identify critical determinants contributing to the high rates of heterosexual HIV transmission in developing countries through a review of studies investigating HIV per-act transmission rates, and to discuss how these factors might be prioritized through HIV-prevention interventions.
Study design: Studies investigating the per-act HIV transmission rate were identified through a MEDLINE search and a review of the abstracts of the Annual International AIDS Conferences.
Results: When the summary mean per-act HIV transmission rates were calculated, the ratio of female-to-male HIV transmission in developing countries compared with that in the developed world was 341, whereas that for male-to-female transmission was 2.9.
Conclusion: Enhanced female-to-male HIV transmission in male core groups is a critical determinant of high-prevalence HIV epidemics among heterosexuals in developing countries. In addition to condom promotion, there is a need for an increased emphasis on HIV-prevention activities in men to decrease their susceptibility in developing countries, particularly in the countries most affected by the epidemic.