🔄 The SIS Compartmental Epidemic Model: Reinfection Without Immunity
The Susceptible–Infectious–Susceptible (SIS) model is a classical framework used to describe the spread of infectious diseases that do not confer lasting immunity. Individuals transition between being susceptible (S) and infectious (I), with recovered individuals immediately returning to the susceptible class. This structure is appropriate for non-immunizing infections, such as the common cold, gonorrhea, or certain … Read more