“Actions Imposed by Circumstances”: The Colonial Origins of The Yellow Fever Vaccine Debate, 1940s–1970s

Why did the French neurotropic vaccine against yellow fever remain in global use from 1945 to the early 1980s, despite mounting evidence that it could cause fatal encephalitis in small children? This paper investigates debates over the safety and efficacy of the French Dakar-strain vaccine at the World Health Organization (WHO) in the postwar years. French microbiologists argued for retaining the vaccine, citing millions of successful jabs in colonial Africa during World War II. Critics pointed to well-documented postwar cases of serious adverse effects, and the availability of a safer alternative – the Rockefeller 17-D strain. Investigating the WHO-s debate reveals how postwar decisions to retain the Dakar strain as an emergency option, next to the 17-D vaccine, were shaped by prewar epidemiological data. These, in turn were limited by colonial infrastructure and racialized logics of wartime vaccination campaigns. Though the vaccine was supposed to be used only as an emergency alternative, in practice, its ease of use in West African settings made it the default option during outbreaks for decades.