This is a test. It is a test of the immune system, one of innumerable exams administered by the School of Life. It’s a rough school. Expulsions are permanent. Each test passed, however, allows the next one to be prepared for with greater ease. So there’s no use calling in sick to the test; sooner or later, we all have take it. It’s best to prepare, by knowing what sorts of questions are likely to be on the test, and how to answer them.
A well told tale, both metaphorical and allegorical.