1918 Influenza part 1

  So I'm reading, "Flu, the untold Story of the great influenza pandemic of 1918, and the search for the virus that caused it", by Gina Kolata.  I'm a few chapters in.  I started reading it, because there seems to be a mystery surrounding this particular flu, if it was indeed a flu at all.  Anyhow, I came across something interesting today.
    In the chapter on Swine Flu, page 136 there is an analysis of the 1976 flu outbreak at Fort Dix.  This is what the officials are basing their evidence of a new and deadly pandemic, related to the 1918 flu, and starts the vaccine campaign. pg 136- "One death, thirteen sick men and up to 500 recruits who evidently had caught and resisted the disease, all in on Army camp, were the only established instances of human-to-human swine flu found around the world as February turned into March, the last month of the flu season in the Northern Hemisphere."   The scientists could not compare the Fort Dix virus to the 1918 flu virus, because no one had any samples for comparison.  So, they are basing a possible future epidemic on what then???