>>Just like any other mathematical model, it's a load of assumptions. Like the vaccine itself being top quality, people being otherwise healthy etc etc.
>>The nice thing is that numbers don't lie. The distance between the reality and the result they get is the same as the distance between the reality and the initial set of assumptions.
There's no theory or sophistry in saying that an eradicated disease is back. How did that happen? This is not just theory wonks debating how many angels can dance on the head of a pin: by 2013 measles was eradicated in the US but now there is an epidemic. Lets leave out conspiracy theories and focus on what exactly society has gotten so wrong to seize defeat from the jaws of victory.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1