Polygyny and the spread of HIV in sub-Saharan Africa

Georges Reniers, Princeton University
Jeff Eaton, Imperial College

Using Demographic and Health Survey data from 14 African countries, we study the relationship between polygyny and HIV infection. At the individual level, we find that polygyny positively correlates with HIV status, particularly in regions and countries with high HIV prevalence. At the aggregate level, however, the correlation is negative, suggesting that the practice of polygyny contains the spread of HIV. With that insight we investigate two mechanisms that contribute to different individual and aggregate-level correlations: (1) HIV status-based adverse selection into polygynous unions, and (2) a reduction in the frequency of intercourse in conjugal units of polygynous unions. We find evidence for both, and together they support the proposition that polygynous marriage systems limit the spread of HIV in populations while increasing the risk of infection for seronegative individuals in polygynous unions. We relate these results to recent discussions of concurrency as one of the major factors explaining the differential spread of HIV.