A mysterious disease swept the world in the early 1920s that put people into catatonic states; stiff and immovable like human statues. It was called encephalitis lethargica and it affected over 5 million people worldwide, and then was almost forgotten.
Knowing what we know now, what do you suppose caused this?
Must be a vaxine.
u/SemperSupra has suggested that it could be a food-borne pathogen.