"Rabbi Abraham Nanzig, writing in London in 1785 in the era of smallpox outbreaks, described the halachic basis for exposing a child to variola virus (variolation) to induce immunity against smallpox: “One who undergoes this treatment while still healthy, God will not consider it a sin. Rather, it is an act of eager religious devotion, and reflects the Commandment to ‘be particularly careful of your well-being”’(Deuteronomy 4:15, Table 1C). In the 1850s, distinguished Rabbi Yisroel Lipshutz described Edward Jenner as a “righteous gentile,” for his efforts in developing smallpox vaccination."