Before revision:  Our theory gives a mechanistic explanation why most COVID-19 cases occurred within a few epicenters, at least in the initial phase of the pandemic. By combining real world data, modeling, and numerical simulations we make the case that that the distribution of epidemic prevalence, and possibly that of spreading processes in general, might follow universal rules .
After revision:  Our theory gives a mechanistic explanation why most COVID-19 cases occurred within a few epicenters, at least in the initial phase of the outbreak. Assessing how well a simple dual-scale model predicts the early spread of epidemics, despite the huge contrasts between countries, could help identify critical temporal and spatial scales of response in which to mitigate future epidemic threats .