Which scientist is associated with the development of vaccination as a method of disease prevention?

• A. Koch
• B. Robert Hooke
• C. Edward Jenner
• D. Antonie van Leeuwenhoek

Answer: (C)

Vaccination as a preventive method arose from the idea that exposure to a related, milder pathogen could teach the immune system to fight a more dangerous one. Edward Jenner connected cowpox infections in dairy workers to immunity against smallpox and tested this by vaccinating a boy with cowpox material, then showing that he did not develop smallpox after later exposure. This experiment demonstrated that deliberate, controlled exposure could induce protective immunity without causing the deadly disease, initiating the practice of vaccination and giving us the term itself, linked to the cowpox source. While other figures listed contributed foundational advances in microbiology and microscopy—such as identifying disease-causing bacteria or describing cells and microbes—they did not pioneer vaccination as a preventive approach.