Edward Jenner is credited with creating the first vaccine. In 1796, Jenner conducted an experiment that led to the development of the smallpox vaccine, using material taken from cowpox lesions. His work laid the groundwork for the field of immunology and paved the way for vaccines that have since eradicated or controlled many infectious diseases. Vaccination has become one of the most effective public health measures, saving millions of lives worldwide. Jenner's innovative approach demonstrated the potential of immunization in preventing disease and has had a lasting impact on global health practices throughout history.