Before revision:  The main differences between this modified SIR model and original SIR one are presented and explained in terms of the zeroes of their respective conserved quantities . We recall that both models have been recently used in order to describe the essentials of the dynamics of the COVID-19 pandemic .
After revision:  The main differences between this modified SIR model and original SIR one are presented and explained in terms of the zeroes of their respective conserved quantities .