Before revision:  It is shown  that during the fast phase, the number of new infected cases in several countries depends on the total number of cases by a power-law relation with a scaling exponent equal to 0.82.
After revision:  It is shown by the first model that during the fast phase, the number of new infected cases in several countries depends on the total number of cases by a power-law relation with a scaling exponent equal to 0.82.