Modern public-health initiatives in industrialized countries revolve around immunization against contagious diseases. The practice of engendering immunity against disease through disease first emerged in Western European social and medical landscapes in the eighteenth century as inoculation, based on the imported Middle Eastern practice of 'engrafting'. By the nineteenth century, this practice had evolved into the procedure of vaccination, in the first instance directed against smallpox. Popular and academic narratives thus often categorize inoculation as a procedure from the Middle East which was transformed into the truly scientific procedure of vaccination by English and French knowledge. This characterization has obscured the complex traditions of intellectual exchange between English and French networks and Middle Eastern societies in the eighteenth and nineteenth centuries. This article examines these networks in order to show how knowledge was transformed as it circulated between communities during this period. Both Western Europeans and Egyptians across different social hierarchies translated foreign or new medical practices according to the needs of their knowledge and goals, creating cycles of adoption and adaptation. This exploration of inoculation and vaccination furthers our understanding of the bilateral translation processes ingrained in the global circulation of knowledge.