Objectives: Heterosexual transmission has long been considered the predominant route of transmission of HIV-1 in sub-Saharan Africa. However, some have argued that unsafe medical injections account for the majority of transmission in this region.
Goal: The goal of this study was to compare the HIV-1 epidemics associated with different transmission routes.
Study: An age-structured deterministic compartmental model of HIV-1 transmission through both sexual contact and unsafe injections was developed and simulations of sexual transmission and iatrogenic transmission were compared with observed prevalence.
Results: Iatrogenic transmission probabilities and numbers of unsafe injections required to generate observed prevalence are unfeasibly high. Simulations of sexually transmitted HIV-1 generate observed prevalence using transmission probabilities and average partner change rates that are within plausible bounds.
Conclusions: Heterosexual transmission seems a more likely route of transmission in the region. However, heterogeneity in contact patterns is of key importance. Further information on groups who are likely to receive more injections is required.