Modeling the viral infectious disease from infection to epidemic

Mathematical models can integrate different components of an infectious disease to reveal novel insights into the long-term effects. Conventional models focus either on pathogen infection (in-host scale) or pathogen transmission (between-host scale). However, we have yet to establish a framework that unites the two scales. We employ a conceptual modeling approach, where the standard transmission parameter becomes a function of the viral load, coupling in-host virus kinetics with an immune response to a compartmental disease model. The stability of the steady states with simulations cast light on the extent of a chronic host infection to influence the severity of an outbreak. Our results lend support to the 'multiscale' paradigm of disease modeling, which can inform long-term, personalized, and data-driven strategies in disease control and healthcare.