Effective containment explains sub-exponential growth in confirmed cases of recent COVID-19 outbreak in Mainland China

Benjamin F Maier; Dirk Brockmann

The model defined by Eqs. (1)-(3) and discussed here indicates that this type of behavior can generally be expected if the supply of susceptible individuals is systematically decreased by means of implemented containment strategies or behavioral changes in response to information about the ongoing epidemic. Unlike contagion processes that develop without external interference at all or processes that merely lead to parametric changes in the dynamics, our analysis suggests that non-exponential growth is expected when the supply of susceptibles is depleted on a timescale comparable to the infectious period assiociated with the infection. The effective depletion of the susceptible populations on a timescale κ −1 0 in the model does not imply that the pool of susceptibles must be depleted in a physical sense. Rather, this depletion could be achieved indirectly.