Britannica Sources used in this answer

Who were Sarah Nelmes and James Phipps in Edward Jenner’s first vaccination experiment?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Infographic showing estimated lives saved by childhood vaccinations worldwide from 1974 to 2024, with syringe-shaped bars for each disease. Measles tops the list at 93.71 million lives saved, followed by tetanus, whooping cough, and others, for a total of 153.84 million lives saved. — vaccine Vaccines and the estimates of lives saved over the period 1974–2024.

In Edward Jenner’s pioneering 1796 experiment, Sarah Nelmes and James Phipps played central roles in the development of the smallpox vaccine:

Sarah Nelmes: A young dairymaid who had contracted cowpox. Jenner identified fresh cowpox lesions on her hand, which provided the biological material necessary for his experiment.12
James Phipps: An eight-year-old boy who had never contracted smallpox. On May 14, 1796, Jenner inoculated Phipps with matter taken from Nelmes’s lesions. After Phipps recovered from a mild illness, Jenner later exposed him to smallpox matter on July 1. Phipps did not develop the disease, demonstrating that the cowpox inoculation had provided immunity.12

This successful trial confirmed Jenner's hypothesis that cowpox could serve as a protective mechanism against smallpox, ultimately leading to the global practice of vaccination.12