Harry, this clip talks about how vaccines can be made safer (ex. Polio):
http://www.pbs.org/wgbh/nova/body/po...e-history.html
Narrator: All up, it took nearly ten years to effect change. In late 1999, the U.S. government announced the switch. The U.K. and Australia followed suit several years later. However, in parts of the world where wild polio remains a threat, the cheaper oral vaccine is still preferred.
John Salamone:
This vaccine had a problem, and there was a better one and we fixed it. It worked—the system worked. It took a while. Too many had to suffer, but the system worked.
A new kind of tattoo vaccination that won't require injection by needle:
http://www.pbs.org/wgbh/nova/body/ti...-vaccines.html