The 1918 outbreak actually occurred in 1917. It started at a military base in Kansas, Camp Funston, not Spain. The first instances appeared around October and November, shortly after vaccinations among troops (Frederick L. Gates, 1918, p. 449).
The Rockefeller Institute played a key role. They produced the vaccine (Frederick L. Gates, 1918, p. 452) and led all studies on the effect it had on the troops (Frederick L. Gates, 1918, p. 455).
At first, people injected suffered mild symptoms, headaches, fevers and discomfort in arms (Frederick L. Gates, 1918, p. 454). But near the end of the trials, adverse reactions in some became quite severe. A few experienced a never seen before symptom, diarrhea. Other became bed ridden with more headaches, joint pains, and nausea (Frederick L. Gates, 1918, p. 461).
