On May 14, 1796, using matter from Nelms’ lesions, he inoculated an 8-year-old boy, James Phipps. Subsequently, the boy developed mild fever and discomfort in the axillae. Nine days after the procedure he felt cold and had lost his appetite, but on the next day he was much better. In July 1796, Jenner inoculated the boy again, this time with matter from a fresh smallpox lesion. No disease developed, and Jenner concluded that protection was complete.
Nearly two years were to elapse between Dr. Edward Jenner's first vaccination in May 1796 and his subsequent experiments, which began in March 1798. In all, perhaps 15 persons were vaccinated. Publication of the findings quickly followed. Jenner published at his own expense, in September 1798, his now famous Inquiry (shorthand for its proper title, An Inquiry into the Causes and Effects of the Variolae Vaccinae, a Disease Discovered in Some of the Western Counties of England, Particularly Gloucestershire, and Known by the name of the Cow Pox).
By the summer of 1799, Jenner's observations had been confirmed by a number of practitioners, and upwards of 1000 persons had been given the vaccine.
Subsequently, Jenner followed-up his original publication with a 1799 “Further Observations on the Variolae Vaccinae,” in which he detailed how to recognize typical Cow Pox lesions and to discriminate them from other similar pustular lesions that were not Cow Pox.
First vaccination by Edward Jenner