1879

The first laboratory vaccine was developed by Louis Pasteur for chicken cholera, an innovation now considered to be the birth of immunology. The concept of employing attenuated (or weakened) bacteria was actually a serendipitous discovery, after Pasteur’s lab assistant forgot to inject their chickens with fresh bacteria and instead used bacteria from a month earlier. Chickens inoculated with the old cultures became protected against the most virulent strains of bacteria. In his paper announcing these findings, Pasteur also used the term vaccination, in honor of the discoveries by Jenner that had inspired his own work.