Exploring the Relationship between Adherence to Treatment and Viral Load through a New Discrete Simulation Model of HIV Infectivity

Human immunodeficiency virus (HIV) has been a major health problem throughout the world for decades. This paper introduces a new discrete simulation model for the growth of HIV infection within a host body. The model is developed incrementally, and compared at each stage for congruence with real-world observations of disease dynamics. We used the model to get a better understanding of how HIV-infected cells behave, and particularly to assess the importance of medication adherence for effectiveness of treatment. We found that a small lack of adherence could have a proportionally much larger impact on infection as well as trigger negative effects on health sooner. Consequently, improving adherence can be very beneficial (particularly for those whose adherence is already high), and small issues in adherence should be addressed early on. Our work is one step in the development of detailed discrete simulations for HIV dynamics. However, much work remains to be done in order to accurately capture adherence as well as medication schedule, viral resistance, or multiple medication types.