Multi-route respiratory infection: when a transmission route may dominate

Caroline X. Gao; Yuguo Li; Jianjian Wei; Sue Cotton; Matthew Hamilton; Lei Wang; Benjamin J Cowling

In this paper, we first provide comprehensive definitions of transmission routes which incorporates the underlying physical principles of multi-route transmission. Second, we establish a more advanced simulation model to describe the infection via different routes considering the physical components of particles and droplets movement, differences in possible viral dose-effect as well as human-behavior factors such as touching mouth and nose. We use influenza as an example due to the large number of related studies for extracting modelling parameters. Using the model, we aim to challenge the traditional dichotomous thinking of close contact transmission vs airborne (aerosol) transmission via highlighting the scenarios under which each transmission route may dominate and how environmental and behavior factors interact in the transmission mechanism.