Before revision:  In the most aggressive mode, the saturation of the number of infections can be achieved sufficiently quickly , though it can be not the end of the epidemic. The square root of the intensity of hard measures is qualitatively inversely proportional to the epidemic duration. We use the theory of Bessel functions.
After revision:  In the most aggressive mode, the saturation of the number of infections can be achieved sufficiently quickly . Our 2-phase formula matches very well the total numbers of infections for Covid-19 in many countries; modeling the first phase is based on Bessel functions.