Edward Jenner is known for creating the first vaccine. In 1796, he developed the smallpox vaccine by using cowpox material, which provided immunity against the more deadly smallpox virus. Jenner's innovative approach laid the foundational principles for immunology and vaccine development, as he demonstrated that exposure to a less harmful pathogen could prevent a more severe disease. His work significantly contributed to the eventual eradication of smallpox, a disease that once caused widespread mortality. Jenner's pioneering efforts continue to inspire research in vaccine development for various infectious diseases, showcasing the enduring importance of vaccination in public health.