Nine-year-old Joseph Meister had been mauled by a rabid dog. His distraught mother brought the boy to see Louis Pasteur, who had recently announced to the French Academy of Sciences that he had successfully protected dogs from rabies by use of his attenuated rabies vaccine. Could he help her son? Pasteur had never successfully used his vaccine in a human, nor was he a medical doctor, but he felt certain the boy would die if he did nothing. So Pasteur made a bold decision and began a course of 13 injections, once daily. The vaccine was a success, and young Joseph survived.
Reference: Berche P. Clin Microbiol Infect. 2012;18(Suppl 5):1-6.