A vaccine is a biological product that helps humans or other animals develop immunities that protect them from one or more diseases. English doctor Edwin Jenner developed the first vaccine in 1796 to create an immunity to smallpox after noticing that women who contracted cowpox from milking cows did not develop smallpox. Jenner used material from these women’s cowpox sores to manufacture his vaccine. This origin gave the word vaccine its name, which is rooted in vacca, the Latin word for cow. This first vaccine generated controversy, and skeptics worried the treatment would turn people into cows. Scientists continued to improve upon Jenner’s smallpox vaccine. In the twentieth century, governments and aid organizations launched programs for
