The Jenner bicentenary: the introduction and early distribution of smallpox vaccine.

This review describes the background to Jenner's first vaccination, his later work, and the dissemination of information about vaccination and the vaccine itself. Although based on relatively slender evidence, Jenner's theories were basically sound and he merits the credit given him. Given the circumstances, particularly the slow speed of travel and the lack of information about the duration of immunity, vaccination became established very quickly in many countries.