Russian-born US microbiologist who developed a highly effective, live vaccine against polio. The earlier vaccine, developed by physicist Jonas Salk, was based on heat-killed viruses. Sabin was convinced that a live form would be longer-lasting and more effective, and in 1957 he succeeded in weakening the virus so that it lost its virulence. The vaccine can be given by mouth.
Red and white were the colours of the Inca Empire. Red represents the blood shed in the fight for independence. White stands for peace and justice. Effective date: 25 February 1825.