Three differential equations modelling HIV virion, and infected and uninfected immune-cell densities during acute and chronic phases of infection underlie in-vivo HIV viral dynamics models. Adding a fourth equation that simulates immunosenesence through the drawdown of a stem-cell reservoir permits the phase of full-blown AIDS to be incorporated in the model. This greatly enhances the utility of the model in designing interventions and explains why time-to-full-blown AIDS decreases with age at infection.
Department of Environmental Science, Policy and Management, University of California, Berkeley, California, USA.
Received 14 August, 2007
Revised 24 October, 2007
Accepted 31 October, 2007