Killed Vaccines: Cholera, Typhoid, and Plague

As reviewed in previous chapters of this work, the earliest vaccines were of the live variety, either based on a naturally occurring weaker version of pathogen, as with Jenner’s use of cowpox, or the laboratory-manipulated, attenuated forms of anthrax and rabies employed by his vaccine heir, Pasteur. The next important concept in vaccine science, killed vaccines, was introduced in animals almost concurrently with Pasteur’s live vaccines, but it took another decade for the realization of its clinical application. In 1886, Theobald Smith and his laboratory chief, Daniel Salmon, developed arguably the first successful, heat killed vaccine against the agent of hog cholera while working at the U.S. Department of Agriculture (Zinsser 1987). In the waning years of the nineteenth century, following closely on the heels of a half-century of stunning advances in microbiology and its sister science, immunology, killed vaccines were developed against three major bacterial causes of human morbidity and mortality of the time that flourished amidst the nineteenth century’s primitive sanitation and underdeveloped public health practices: cholera, typhoid, and plague.