Modelling the spread of HIV among intravenous drug users

This paper considers a random allocation model for the transmission of HIV by needle sharing among a group of intravenous drug users who are friends or relatives (buddy-users). A Markov chain approach is used to track the increase in infectives in a stable group of such IVDUs, some of whom are HIV positive. The model is modified to allow for the replacement of infectives in the group, with the group size remaining constant. Further problems are suggested.