AIDS in sub-Saharan Africa: the role of initial conditions in shaping AIDS trajectories

Marco Boeri, Dipartimento Statistica & Matematica Applicata all'Economia
Piero Manfredi, Dipartimento di Statistica & Matematica Applicata all'Economia
Giampaolo Scalia-Tomba, Università Roma 2

What are the factors that make patterns of HIV/AIDS spread in Sub-Saharan Africa so widely different ? An explaining factor that, comparatively to others, has been less investigated is path-dependency, i.e. the role played by initial conditions in shaping the height of the epidemics trajectories. In this paper we aim to provide new light on this issue by investigating the manner in which the distribution of initial infective seeds might have affected the height of the initial exponential phase of the epidemics, a parameter, that represents the natural counterpart of the well-known stable equivalent arising in classical population theory. This is done for a variety of “classical” models for the transmission dynamics of HIV in developing countries. The results suggest that initial conditions might have played a prominent role in shaping the various SSAF epidemics.