My understanding is that the soldiers were vaccinated before returning home, 
just in case they brought some exotic disease home with them, and this 
apparently was in or around Spain somewhere {sorry of my ignorance} which is 
why it was called the "Spanish Flu".  Spain apparently were quite disturbed and 
annoyed by that term when it had nothing to do with Spain in real terms.
N.

Subject: CS>Spanish Flu - Epidemic of 1918
From: ala...@gmail.com
Date: Thu, 16 Oct 2014 18:48:08 -0700
To: silver-list@eskimo.com

As far as history, it is written by the victors and no one can truly say if the 
Spanish flu was actually a flu or whatever, but to say that vacciation is safe 
because you made it through  is a bit weak.
Alan