Short Teaching Module: Transnational Efforts at Controlling Yellow Fever

Aro Velmet
Photo shows three men in pith helmets with a device on a cart in the foreground. A small hut is in the background.


Early twentieth century microbiologists thought of their work as inherently transnational, and world historians have begun to do the same. The West African yellow fever epidemic of 1927-28 offers an exemplary opportunity to study how French scientists and African politicians used imperial and international networks to reimagine colonial public health policies. If we want to understand why French colonial authorities turned from quarantines and disinfection measures towards vaccination programs, we need to study sources from Dakar, Paris, and New York with equal attention. This module uses three sources to do just that.


How does the history of biomedicine look different, when viewed through a transnational lens? Certainly, neither infectious diseases nor the people who studied them respected borders. In the early twentieth century, epidemics of yellow fever spread across French and British colonial territories in West Africa, as well as Colombia, Brazil and Peru in Southern America. The scientists studying the disease – largely from two big Western institutions, the Rockefeller Foundation in the United States and the Pasteur Institute in France – made their careers traveling between both hemispheres, chasing outbreaks across national and imperial boundaries. Just as infectious diseases spread internationally, the spread of microbiological knowledge neatly outlines the nodes of global power and links the centers of international scientific exchange.

This does not mean, however, that boundaries were irrelevant. Scholars of colonialism have argued that empires were spaces of uneven and lumpy power, where sovereignty was often layered, different legal regimes overlapped and conflicted, and administrators used different repertoires of rule to hold a patchwork of territories together, often with a minimum of fiscal and political support from the imperial center. For Western microbiologists working in colonial spaces, this unevenness of power relations could be both a constraint and a resource. In colonial spaces with less bureaucratic oversight, scientists could conduct trials of vaccines and pharmaceuticals that would have been considered too dangerous or too costly to run in the metropole. Conversely, many research projects that began in tropical regions were eventually moved to imperial centers in Paris or London, since as these project developed, they demanded better infrastructure and denser communities of scientists than West African laboratories could provide. 

We should not assume, though, that the direction of traffic always moved between metropole and colony. Often, neighboring colonies and neighboring empires were more important destinations of travel than European capitals thousands of miles away. Thus, the French yellow fever vaccine project, which began during the epidemic of 1927-28, owes much of its success to the work of a British scientist, Adrien Stokes, who worked with the American Rockefeller Foundation in Lagos, British Nigeria. Stokes managed to cultivate the yellow fever virus in the blood of rhesus monkeys, something the French had been unable to do. When he contracted yellow fever himself, he quickly sent off a letter to his French colleagues working in Dakar, Senegal, outlining the process of virus cultivation. He succumbed to the virus a few days later.

French public health measures themselves were the product of the globalization of knowledge and technologies. Initially, the French fought yellow fever using highly intrusive strategies, such as quarantine and sulphuric disinfection, directed primarily at the African subjects of their West African colonies. Disinfection was performed using Clayton machines, such as the one pictured in the primary sources. The Clayton machine, as Christos Lynteris has shown, was first invented in New Orleans, where it was used to fend off yellow fever, but gained popularity during plague outbreaks in East Asia and Southeast Asia, where it was embraced by the French in colonial Indochina. Indeed, French administrators in West Africa imported many of their public health strategies, which included burning down entire indigenous neighborhoods, forced isolation, and strict curfews, from their experiences of dealing with the plague in Indochina. Imperial circulation was at the heart of microbiological knowledge-making.

Western scientists and colonial administrators were not the only ones who were traveling, though. As yellow fever spread through the West African Federation’s capital city of Dakar, dissatisfaction with draconian public health measures grew. This disgruntlement was amplified by the fact that, in contrast to the plague, French residents of Dakar were more likely to fall gravely ill with yellow fever, while Africans were largely spared. The French response to yellow fever was elevated to a major scandal by Blaise Diagne, the Senegalese deputy in the French National Assembly, who in a series of interviews and articles (an example of which is provided in the primary sources), accused the authorities of overpolicing Africans and underpolicing Europeans, leading to the spread of the disease in the European parts of Dakar. With existing public health measures coming under such forceful attack, the French had to change their strategy. To calm the waters, they invited the prestigious Pasteur Institute to set up shop in Dakar, and develop a vaccine against the disease, a step that Diagne himself applauded. 

The history of the yellow fever vaccine therefore appears as a story of transnational mobility of both science and politics, extending from Indochina to Dakar, and from Dakar to Paris. Yet the story does not end here. The unevenness of colonial institutions played a critical role in the creation of the yellow fever vaccine. When the Pasteur Institute developed its first prototype in Paris, it quickly became evident that the injection could cause serious adverse effects in some patients. As Dr. Georges Stefanopoulo, a Pastorian microbiologist, recounts to his colleagues at the Rockefeller Foundation in one of the primary sources, the vaccine could cause “grave cases of paralysis” in some test subjects, including a woman who fell into a coma for several weeks, before recovering at a Parisian hospital. Under close scrutiny by different regulators and competitors, the Pasteur Institute refused to let the vaccine move to larger human trials. Microbiologists in African colonies, however, were more welcoming. The vaccine was trialed in Tunisia and in Senegal, where Pastorians reported far more success. Some, like Stefanopoulo, however, suspected that this had less to do with improvements to the vaccine and more to do with the lack of medical infrastructure, which made surveilling patients far more difficult. 

We owe much of our knowledge of the French vaccine’s development process to the Rockefeller Foundation – another transnational link in the network of yellow fever researchers. The Rockefeller Foundation was both a competitor with the Pasteur Institute and its supporter. The RF was in the process of developing their own vaccine, the 17D strain, which is still currently in use, but it also funded the research of some Pastorians, such as Stefanopoulo. Correspondence between Rockefeller and Pastorian scientists reflects this tension: collegial exchange of information is interspersed with caution about revealing trade secrets and jeopardizing one side’s victory in the race for an effective yellow fever vaccine. 

Histories of globalization are often described in terms of “flows”, “streams” and “circulations”, evoking images of unimpeded motion, like the current of river, carrying along everything in its path. Transnational histories of biomedicine suggest a different dynamic. The twentieth century was a century of global interconnectedness, indeed, but these connections were neither frictionless nor all-encompassing. Some people traveled, others did not. Some places were more accessible than others – if you had the right connections. Borders and boundaries still mattered. Indeed, it was precisely because they mattered that some actors could take advantage of their ability to travel, and leverage their mobility for various kinds of advantages. Pastorian scientists moved between colonies in search of sites for human trials; African politicians escalated conflicts over public health into national scandals; American scientists put pressure on their French colleagues by pursuing their own vaccine agenda. By thinking of mobility as a kind of politics we can shed new light on the imperial history of Western biomedicine – and on the people who resisted it.

Primary Sources

Disinfection of Dakar houses with a Clayton Apparatus

Photo shows three men in pith helmets with a device on a cart in the foreground. A small hut is in the background.

This is a photograph from the collections of the Rockefeller Archive Center depicting a Clayton apparatus disinfecting African houses during the yellow fever outbreak of 1927. The image illustrates a number of transnational linkages that shaped the epidemic. Clayton apparatuses were steam disinfection devices that used sulphuric gases to destroy pathogens in infected homes. They were originally designed to disinfect ships, and were used in port cities such as New Orleans, Hong Kong and Saigon during outbreaks of the plague and of yellow fever. Disinfection could be extremely unpleasant for the inhabitants of infected houses and often, when sulphuric disinfection was not possible, French authorities would simply burn infected houses to the ground, providing meager indemnities in return. Many of these draconian measures were developed in French Indochina during plague outbreaks in the 1890s, and imported to West Africa as part of a colonial public health toolkit.

It is also remarkable that this photo was taken by someone working for the Rockefeller Foundation. In the 1920s, the Rockefeller Foundation’s International Health Division sought to set up a yellow fever research station in West Africa, where the disease was endemic. The IHD surveyed several possible sites: in French West Africa, Sierra Leone, and British Nigeria. They received a cool welcome from the French, who saw the IHD as a competitor to their own Pasteur Institute. The IHD ultimately established its field site in Nigeria, working with British authorities, and becoming a direct competitor with the Pasteur Institute. The yellow fever pandemic was shaped both by dynamics within the French empire and by interimperial competition.

This source is part of the teaching module on transnational effort to control yellow fever

"Yellow fever in Dakar – There is no epidemic"

Headline of newspaper article "La fièvre jaune à Dakar - Il n’y a pas d’épidémie," explanation at link.

This is an excerpt from an interview with Blaise Diagne, the Senegalese deputy to the National Assembly, published in Le Matin, one of the major national dailies in metropolitan France. The yellow fever outbreak of 1927-28 was quickly politicized by French and African commentators alike. Unlike in the rest of West Africa, African inhabitants of Dakar, one of the four “old colonies,” had voting rights and were, for all intents and purposes, equivalent to French citizens. Some French commentators suggested that it was precisely this “African emancipation” that prevented French health authorities, fearing a backlash in the polls, from imposing tough public health rules, and therefore allowing the epidemic to spread. In this interview, Diagne rejects this claim, noting that the disease is, in fact, spreading in the European quarter, and that Africans have been following public health regulations to the letter. This controversy over health measures, which became a scandal in France proper, prompted the Ministry of the Colonies to sponsor a Pastorian mission to West Africa, leading to the development of the yellow fever vaccine. As this newspaper excerpt illustrates, Africans were just a good as the French at leveraging their pan-imperial connections to achieve political advantages.

The article is titled “Yellow fever in Dakar – There is no epidemic, the Senegalese deputy Mr Diagne tells us, but a scourge spreading endemically for well over a year – Europeans in particular are affected”. In the article, Diagne states the following: “There is no epidemic [...] but, since 1926, endemic spread of yellow fever. The indigenous districts, which are properly surveilled and where the inhabitants have had to follow the measures set by the public health service, have escaped the disease. Europeans, by contrast, who often live in defective but inviolable housing, have been hit much harder. And I can say, without fear of contradiction, that all the cases of yellow fever have documented in European areas of Dakar. There is then no need to turn this problem into a question about the political emancipation of the indigènes. If this explained the spread of yellow fever in Senegal, how would one then explain the spread of the disease in British territories, for example on the Gold Coast or in Nigeria, where the indigènes do not have voting rights?”

This source is part of the teaching module on transnational effort to control yellow fever

Rockefeller Foundation Report Concerning the Yellow Fever Vaccine

Text of report. Transcription at link.

The creation of the yellow fever vaccine turned out to be quite controversial. Many of these controversies are revealed in documents such as this summary of correspondence between Georges Stefanopoulo, a Pastorian microbiologist, and his colleagues at the Rockefeller Foundation in New York. In section 3 of the report, it is noted that Stefanopoulo had concerns with Jean Laigret’s vaccine, which he believed to have caused cases of paralysis, contrary to official reports of trials in Africa, reporting unqualified success. The source also shows the changing landscape of international medical science. The Pasteur Institute, once a central hub of microbiological research, was having increasing difficulties retaining its scientists, while the Rockefeller Foundation was increasingly providing grants to European researchers, such as Stefanopoulo. The collaborative-competitive dynamic between the two institutions characterized much of their interactions in the 1920s and 1930s, including the development of the yellow fever vaccine, which, at least to some Pastorians, became a race to prove the French still held the upper hand in microbiological research.

This source is part of the teaching module on transnational effort to control yellow fever


Aro Velmet is Assistant Professor of History at the University of Southern California. He received his PhD from New York University in 2017. He is a historian of science, technology, and medicine in imperial settings throughout the twentieth century. His book, Pasteur’s Empire: Bacteriology and Politics in France, its Empire, and the World (Oxford University Press, 2020) explores the role colonialism played in the emergence of modern microbiology. He is currently working on the history of standardized vaccination campaigns, and a history of information processing in the socialist East.

How to Cite This Source

"Short Teaching Module: Transnational Efforts at Controlling Yellow Fever," in World History Commons, https://worldhistorycommons.org/short-teaching-module-transnational-efforts-controlling-yellow-fever [accessed May 22, 2022]