Sir Ronald Ross is famous for being the discoverer of the mosquito transmission of malaria and the first Briton to be awarded the Nobel Prize for Medicine.
Robert Koch discovered the anthrax disease cycle and the bacteria responsible for tuberculosis and cholera. He received the Nobel Prize for Physiology or Medicine in 1905 for his research on tuberculosis.
The smallpox vaccine, introduced by Edward Jenner in 1796, was the first successful vaccine to be developed.
Alexander Fleming was a doctor and bacteriologist who discovered penicillin, receiving the Nobel Prize in 1945.