Below you will find links to each of the 7 parts to a series titled Age of Polio: How an Old Virus and New Toxins Created a Man-made Epidemic.  This was written by Dan Olmsted and Mark Blaxill.  They did extensive research into polio and what was going on at the same time to try to answer some questions about polio that hadn't been answered.  Very informative and worth a read. 

Part 1: The Wrong Narrative
Part 2: A Gypsy Moth Flaps Its Wings
Part 3: Making Sense of Campobello
Part 4: Post-War Epidemics and the Triumph of Vaccinations
Part 5: Before
Part 6: After: The Persistence of Polio
Part 7: "Where Was God" Lessons Learned and Lost