Compartmental Models in Epidemiology - The SIS Model

The SIS Model

Some infections, for example the group of those responsible for the common cold, do not confer any long lasting immunity. Such infections do not have a recovered state and individuals become susceptible again after infection.

We have the model:

Note that denoting with N the total population it holds that: it follows that:

i.e. the dynamics of infectious is ruled by a logistic equation, so that :

Read more about this topic:  Compartmental Models In Epidemiology

Famous quotes containing the word model:

    For an artist to marry his model is as fatal as for a gourmet to marry his cook: the one gets no sittings, and the other gets no dinners.
    Oscar Wilde (1854–1900)