BACKGROUND
Empirical estimates of the female-to-male ratio of infections in generalized HIV
epidemics in sub-Saharan Africa range from 1.31 in Zambia to 2.21 in Ivory Coast.
Inequalities in the gender ratio of infections can arise because of differences in
exposure (to HIV-positive partners), susceptibility (given exposure), and survival (once
infected). Differences in susceptibility have to date received most attention, but neither
the relatively high gender ratio of infections nor the heterogeneity in empirical
estimates is fully understood.
OBJECTIVE
Demonstrate the relevance of partnership network attributes and sexual mixing patterns
to gender differences in the exposure to HIV-positive partners and the gender ratio of
infections.
METHOD
Agent-based simulation model built in NetLogo.
RESULTS
The female-to-male ratio of infections predicted by our model ranges from 1.13 to 1.75.
Gender-asymmetric partnership concurrency, rapid partnership turnover, elevated
partnership dissolution in female-positive serodiscordant couples, and lower partnership
re-entry rates among HIV-positive women can produce (substantial) differences in the
gender ratio of infections. Coital dilution and serosorting have modest moderating
effects.