The first successful vaccine was introduced by Edward Jenner in 1796. Which disease did it guard against?
https://www.onlinefreelancersnetwork.com/wp-content/uploads/2020/08/logoOFN.png00Frank Mainhttps://www.onlinefreelancersnetwork.com/wp-content/uploads/2020/08/logoOFN.pngFrank Main2021-07-30 23:38:172021-07-30 23:38:17The first successful vaccine was introduced by Edward Jenner in 1796. Which disease did it guard against?