Variolation already exists back then, but with a survival rate of 1-2%. What Edward Jenner did was to confer scientific status on the idea of vaccination and in

Variolation already exists back then, but with a survival rate of 1-2%. What Edward Jenner did was to confer scientific status on the idea of vaccination and investigated cowpow as a much safer method of inoculation against smallpox. Heck, decade earliers, George Washington inoculated his troops against smallpox against the wishes of the continental congress.