The origins of modern smallpox vaccines Smallpox vaccination using a hete rologous species oforthopoxvirus (OPXV) became common practice after EdwardJenner’s famous experiment in which he inoculated a young JamesPhipps with material from a cowpox (CPXV) lesion in 1796 [1].Early reports on the effectiveness of pre-exposure vaccinationwere confirmed by well-documented studies performed through-out the 19th century which demonstrated significantly lower ratesof smallpox mortality in geographic areas with mandatory vacci-nation as opposed to areas where vaccination was not required