You've asked an intriguing question! The polio vaccine changed life a lot. Polio can be a devastating disease. 1 in 500 people who get it end up paralyzed. That doesn't seem like a lot of people, but if a million people get polio, 20,000 people end up paralyzed. Polio is also an emotionally difficult disease to deal with. It generally infected children, and most parents find it very hard to deal with their children being sick. And it strikes very rapidly--within hours of being infected, you got symptoms (compare this to chicken pox where it can take up to three weeks to get the disease). Plus there tended to be epidemics of it, with children often contracting it in the summer when they spent a lot of time playing with their friends.

Back in the 1940's there were several competing groups who were trying to develop a vaccine against polio. Jonas Salk and Albert Sabin both were trying to develop a vaccine. In the end Salk won out, and tested his vaccine on himself! Today, polio is one of only a few diseases (the other notable case is smallpox) which has been eradicated by massive vaccination projects worldwide.

Here's some websitest that give you information about Salk, Sabin and polio itself.

• http://search.eb.com/bol/top ic?idxref=525428
• http://search.eb.co m/bol/topic?eu=122544&sctn=1#s_top
• http://search.eb.com /bol/topic?eu=66295&sctn=1#s_top