Bubonic plague vaccine

The bubonic plague vaccine emerged from the convergence of germ theory, colonial crisis, and the Pasteur Institute network. For centuries, plague had killed millions with no defense beyond quarantine and flight. Then, in less than three years, science moved from identifying the bacterium to mass-producing a vaccine—a transformation that demonstrated how quickly medicine could move when the right conditions aligned.

The prerequisites fell into place rapidly. In 1894, during a plague outbreak in Hong Kong, Alexandre Yersin and Shibasaburo Kitasato both identified the causative bacterium (later named Yersinia pestis after Yersin). In 1895, Yersin showed that heat-killed bacteria could produce immunity in animals. The theoretical foundation for a vaccine existed. What was needed was someone to develop it for humans.

That someone was Waldemar Haffkine, a Russian-born bacteriologist who had already developed a cholera vaccine at the Pasteur Institute in Paris. When bubonic plague struck Bombay in October 1896, the British Indian government called for help. Haffkine set up a makeshift laboratory in a corridor of Grant Medical College and began adapting Yersin's findings for human use.

The work was brutal. Of his initial assistants, one had a nervous breakdown and two quit. But in three months, Haffkine had a preparation ready for testing. On January 10, 1897, he tested it on himself, experiencing mild fever but no severe effects. He then administered it to prisoners during the Bombay outbreak, demonstrating significant protection against the disease.

The scale of what followed was unprecedented for a bacterial vaccine. Between 1897 and 1925, over 26 million doses of Haffkine's anti-plague vaccine were shipped from Bombay throughout the British Empire. Mortality rates among vaccinated populations dropped by 50-85 percent. Joseph Lister called Haffkine 'a saviour of humanity.'

The vaccine was a heat-killed whole-cell preparation—Yersinia pestis grown in broth, inactivated by heat, and injected to provoke immune response. It was crude by modern standards and required multiple doses, but it worked. Haffkine's vaccine proved that prophylactic vaccination could control bacterial epidemic disease, opening the path for vaccines against typhoid, tuberculosis, and other bacterial threats.