Who is credited with developing the first vaccine?

Edward Jenner is credited with developing the first vaccine, the smallpox vaccine. In 1796, the English physician tested the idea that infection with cowpox, a much milder disease, could protect people from the deadly smallpox virus.

On 14 May 1796, Jenner inoculated eight-year-old James Phipps with material from cowpox lesions taken from Sarah Nelmes, a milkmaid. Jenner later exposed Phipps to smallpox material and observed that the boy did not develop the disease. Jenner published his findings in 1798 in An Inquiry into the Causes and Effects of the Variolae Vaccinae, a work that helped establish vaccination as a medical practice.

Jenner did not invent the broader idea of deliberately creating immunity. Variolation, an older practice involving exposure to smallpox material, had been used in parts of Asia, Africa, and the Ottoman Empire. Benjamin Jesty had also used cowpox to protect his family in 1774. Jenner’s achievement was systematically investigating, documenting, and promoting cowpox protection, allowing the method to spread widely.

The word vaccine comes from the Latin vaccinia, meaning cowpox. Jonas Salk later developed a famous polio vaccine, but he was not the creator of the first vaccine.