12 April 1955 April 11, 2012 Author: Staff The polio vaccine is declared safe and effective. Famous Words of Inspiration..."I keep six honest serving-men (They taught me all I knew); Their names are What and Why and When And How and Where and Who." Rudyard Kipling — Click here for more from Rudyard Kipling No related posts. Categories: History Tags: 12 April, 1955