Before revision:  ii ) that the temporal evolution of the cumulative number of infected people follows a distorted Fermi-Dirac-like distribution function; iii ) the key role played by the quarantine in the prevention of the spread of Covid-19 in terms of an interacting \emph{ parameter, which emulates the contact between infected and non-infected people.
After revision:  ii ) that the temporal evolution of the cumulative number of infected people follows a distorted Fermi-Dirac-like function; ) the key role played by the quarantine in the prevention of the spread of Covid-19 in terms of an interacting \emph{ parameter, which emulates the contact between infected and non-infected people.