Before revision:  In addition, the reduction in transmission associated with physical distancing between the host and susceptible as well as the level of physical activity  of the host and /or the susceptible in enhancing transmission risk, is also examined .
After revision:  In addition, the reduction in transmission associated with physical distancing between the host and susceptible as well as the level of physical activity (or exercise intensity) of the host and /or the susceptible in enhancing transmission risk, is also examined .