Louis Pasteur is credited with inventing the first successful vaccine for rabies. In the late 19th century, Pasteur developed a vaccine using weakened strains of the rabies virus, effectively preventing the disease in those exposed to rabid animals. His groundbreaking work in microbiology laid the foundation for modern immunology and vaccination techniques. Pasteur's rabies vaccine was first used in 1885 on a young boy who had been bitten by a rabid dog, marking a significant milestone in medical science. His contributions to vaccines and germ theory have had an enduring impact on public health and disease prevention.