  The Covid-19 epidemic of the novel coronavirus (severe acute respiratory
syndrome SARS - CoV-2) has been spreading around the world. While different
containment policies using non-pharmaceutical interventions have been applied,
their efficiency are not known quantitatively. We show that the doubling time
Td(t) with the success s factor, the characteristic time of the exponential
growth of Td(t) in the arrested regime, is a reliable tool for early
predictions of epidemic spread time evolution and it provides a quantitative
measure of the success of different containment measures. The efficiency of the
containment policy Lockdown case Finding mobile Tracing (LFT) using mandatory
mobile contact tracing is much higher than the Lockdown Stop and Go (LSG)
policy proposed by the Imperial College team in London. A very low s factor was
reached by LFT policy giving the shortest time width of the dome of positive
case curve and the lowest number of fatalities. The LFT policy has been able to
reduce by a factor 100 the number of fatalities in the first 100 days of the
Covid-19 epidemic, to reduce the time width of the Covid-19 pandemic dome by a
factor 2.5 and to rapidly stop new outbreaks avoiding the second wave
