“…Some people have innated or vaccine immunity against certain diseases, and there is a MSIR model that expresses them with M. Over time, new compartmental models have been developed by considering various disease dynamics and additional compartments such as exposed, dead cases, maternally derived immunity, and insusceptible. Other example models include SEI [45], SIRS [46,47], MSEIR [48], SEIRV [49], SEIJR [50], SEIHR [51], SEIRD [14,29], SEIARD [15], SEIAQRDT [52], SEIQRDP [53] and SPEIQRD [54,55].…”