26 mar 1953 año - Jonas Salk created the polio vaccine
Descripción:
Due to Jonas Salk's experiments and the development of the polio vaccine, the amount of polio cases fell dramatically in the second half of the twentieth century. Today it is almost completely gone in developed countries. The discovery of the vaccine proved that animal testing is beneficial to humans despite the treatment of animals when tested on.
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CM Timeline Animal Testing Controversy
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