  We revisit here a landmark five parameter SIR-type model of [DvdD93, Sec. 4],
which is maybe the simplest example where a complete picture of all cases,
including non-trivial bistability behavior, may be obtained using simple tools.
We also generalize it by adding essential vaccination and vaccination-induced
death parameters, with the aim of revealing the role of vaccination and its
possible failure. The main result is Theorem 5, which describes the stability
behavior of our model in all possible cases.
