Poorly known aspects of flattening the curve of COVID-19

This work concerns the too-often mentioned flattening of the curve of COVID-19. The diffusion of the virus is analyzed with logistic-curve fits on the 25 countries most affected at the time of the writing and in which the diffusion curve was more than 95% completed. A negative correlation observed between the final number of infections and the slope of the logistic curve corroborates a result obtained long time ago via an extensive simulation study. There is both theoretical arguments and experimental evidence for the existence of such correlations. The flattening of the curve results in a retardation of the curve’s midpoint, which entails an increase in the final number of infections. It is possible that more lives are lost at the end by this process. Our analysis also permits evaluation of the various governments’ interventions in terms of rapidity of response, efficiency of the actions taken (the amount of flattening achieved), and the number of days by which the curve was delayed. Not surprisingly, early decisive response proves to be the optimum strategy among the countries studied.