Louis Pasteur successfully tested his rabies vaccine on this day in 1885. Pasteur had begun work on a vaccine in 1882, using a weakened form of the virus taken from the spinal cords of infected animals. The research was time-consuming, because it took several weeks for the virus to reach his test animals’ brains after they were infected, but Pasteur soon realized that people didn’t need to have the vaccine on board before they were bitten, as with other diseases. The delay between the rabid animal’s bite and the outbreak of the disease meant the vaccine could be given only when needed, and it would have plenty of time to work.
In 1885, a nine-year-old boy named Joseph Meister was bitten by a rabid dog. He was brought to Pasteur, and though Pasteur didn’t feel his vaccine was sufficiently tested yet, he knew the boy would certainly die otherwise, so he took a chance. It was a tense few weeks waiting to see if Meister would come down with the disease, but the boy recovered, and three months later was pronounced in good health. Pasteur’s fame spread quickly, and the era of preventative medicine had begun.