Practical models for the care of HIV and AIDS patients

Mathematical models for infectious diseases are of lim ited use in providing practical help to health professionals. In this paper we discuss computer models developed jointly by operational research mathematicians and clinicians to meet this need. W e use the term 'operational modelling' to describe this pragm atic approach. The models can aid decision-making at a resource planning level and can also be used by clinicians to monitor and im prove patient care. The models incorporate uncertainty and variability and are therefore mathematically complex, but are easy to use and provide a great deal of useful information about morbidity and resource use.