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.
The star represents Islam and expresses peace, harmony, hope, and socialism. The tricolour is reminiscent of the flag of France, the former colonial power. The pan-African colours express unity with other African nations. Effective date: 25 August 1960.