“…Fractional operators have received increasing interest by several directions in the modeling of biological process. Let us brefly review one of the recent papers, in [34] for exemple, the authors proposed and studied the dynamics behavior of COVID-19, that was by analysed an SEIHDR model based on ABC operator, they showed the transmission dynamics of COVID-19 after they analysed the existence results, see [1,2,13,12,11,21,8,7,6,18,19,20,16,10,9,23,24,29,31,32,33] and the references therein.…”