Sheilagh Ogilvie 

The Covid-19 pandemic rightly focused our attention on medical science. But working on economic history and historical demography, I’ve always been struck by how the outcomes of epidemics are shaped by more than microbes and medicines. Why did some societies suffer so much more than others? Why were some life-saving innovations adopted quickly in one place, but rejected for decades just a few miles away? 

My new book, Controlling Contagion: Epidemics and Institutions from the Black Death to Covid, argues that we can answer these questions by looking at deep social structures. The key, I suggest, lies in understanding our social “institutions”—the rules of the game that structure how we cooperate inside society. 

The double-edged sword of institutions 

When I use the term “institution,” I don’t just mean a formal organisation. I mean a system of rules, customs, and practices that channels how people interact. In the book, I analyse how six key institutions have historically mediated the fight against contagious disease: 

• The market 
• The state
• The local community
• Religion
• The occupational association (guild)
• The family

My research suggests that each of these institutions is a double-edged sword. Each has a “bright side” that can help control contagion, and a “dark side” that can fail to do so, or even actively make things worse. 

The market, for instance, generates the economic growth needed for families and individuals to protect themselves against disease, governments and communities to fund public health infrastructure, and churches and charities to help the poor comply with anti-contagion measures. But the market also creates pathways such as trade and migration along which pathogens travel, and it fails to price the “negative externality”—the uncompensated harm—of one person infecting another.  

Likewise, the state can enforce quarantines and fund public health, but it can also wage wars that spread disease and drain resources that could have been used for civilian well-being. Recognizing the Janus face of every human institution, I hope, can provide a useful analytical tool for historical research. 

New light on old demographic questions 

Writing this book required delving into many of the foundational questions that researchers at Campop and in the wider field of historical demography have been working on for decades. My goal was to see how the lens of epidemic disease might offer new perspectives on economic history—and vice versa.

1. The “epidemiological transition” 

A central concept in demographic history is the “epidemiological transition”—the long-term decline in death rates, during which populations move from high mortality caused by infectious diseases to low mortality where chronic, degenerative diseases are more important than infectious ones. My work suggests this transition was not a smooth, linear path driven solely by scientific discovery and medical innovation. Instead, it was a messy and conflictual process, where the acceptance of new ideas and practices was either blocked or enabled by social institutions. 

Take smallpox variolation. This successful immunization procedure was practised for centuries in Asia, Africa, and the Middle East before its introduction to Europe in the 1720s. Why did it then face such fierce resistance in France, Spain, and parts of Germany, while being more readily adopted in England, Scotland, and Ireland?

The answer I found lies in the differing institutional landscapes. In France and Spain, powerful medical guilds saw variolation as a threat to their monopoly on medical knowledge, and religious bodies condemned it as a violation of divine will. In Britain, a less rigid institutional framework allowed commercial practitioners and local communities more freedom to experiment. The path to mortality decline was thus carved not just by new ideas, but by the institutions that paved or blocked their way.  

Thomas Hickey, Queens of Mysore (1805). On the left, Krishnaraja Wadiyar III’s first wife, Devajammani, has a discoloration around the mouth, thought to be due to the blowing of variolation dust in the nose. On the right, his second wife shows the discrete mark left by vaccination under her sari.

2. Rethinking family, household, and gender

For historical demographers, the family is a foundational institution, and its connection to epidemic outcomes is a fascinating puzzle. Our field has long been shaped by John Hajnal’s distinction between the “European Marriage Pattern” (EMP)—with its late marriage and nuclear households—and family systems elsewhere that favoured early marriage and extended, multi-generational living. 

A common assumption is that the smaller, simpler households of the EMP must have been better at limiting contagion. Larger, more complex households increase a disease’s “secondary attack rate“, exposing more people of different ages and immunities to infection. 

But while this is a powerful theoretical argument, the historical evidence is much messier. The link between household size and mortality was often confounded by wealth. In some contexts, like 17th-century London and Florence, the poor were more vulnerable even though they lived in smaller households; only by controlling for wealth and status, as in 17th-century Nonantola or Eyam, can we identify the distinct effect of household size. Household structure, moreover, was often an economic response to the surrounding institutional framework, not a fixed cultural norm. 

I also looked at the popular “girlpower” hypothesis: that the EMP empowered women. Women with greater autonomy might then have made better health decisions for their families. But what I found was a story of widespread female agency that transcended any single family system. Women were the driving force behind the adoption of immunization—both variolation and later vaccination—in an astonishing variety of societies: in EMP England, but also in non-EMP Ottoman Turkey, Spain, Russia, and India. The family system was not the decisive factor. Instead, women’s ability to protect their families was shaped by the whole institutional framework, which could either support female agency or, as when medical associations created monopolies, stand in its way. The family’s role, I conclude, can never be understood in isolation. 

Spanish mother vaccinating her son, 1802. This illustration was inserted at the end of a Spanish pamphlet, consisting of an adaptation of a French broadsheet which offered a “how to” manual on vaccination for ordinary people. The Spanish author included illustrations at the end of his pamphlet in order to demonstrate how to implement the procedure. P. Hernández, Orígen y descumbrimiento de la vaccina / traducido del frances con arreglo a las ultimas observaciones… (1802), p. 75

3. The local community

The local community might look too puny to deal with a pandemic—a 90-pound weakling confronting a steroid-pumped colossus. But it has a special superpower: “social capital”. This term refers to the trust, shared norms, and dense networks of information that arise when people live in close proximity and know each other well. 

In historical epidemics, communities used their social capital to great effect. Long before formal public health systems, neighbourly peer pressure enforced communal sanitation. In late medieval Ghent, for instance, neighbourhood associations monitored and reported people who carelessly disposed of infectious waste. During the hookworm epidemics in the early–20th-century American South, the Rockefeller Foundation harnessed this same power, publishing maps pinpointing households that had failed to upgrade their latrines—a public shaming that proved highly effective. Communities also organized social distancing, as during smallpox epidemics in 18th-century Indonesia, where “silent barter” was used to trade with outsiders without face-to-face contact; or in 19th-century Ethiopia, where peasant villages posted guards to keep out travellers from afflicted areas.  

But communal social capital has a dark side. The same trust and shared norms that can enforce sanitation or social distancing can also organize resistance to public health measures, as with the communal anti-quarantine and anti-vaccination riots that erupted during pandemics from the Black Death to Covid-19. The same information networks that identify who is sick can also spread false rumours and fuel “information cascades”. In the 1630 Milan plague, for instance, communal rumour claimed that infection was spread by malicious “anointers” (untori), innocent scapegoats who were tortured and executed. 

Plague riot in Moscow, 1771. From 15 to 17 September 1771, thousands of Muscovites flooded into Red Square to demonstrate against urban quarantines and closures. The mob invaded the Kremlin, razed a monastery, killed an archbishop, and destroyed two quarantine zones before being suppressed by the army.

Perhaps the greatest weakness is that the local community is literally parochial. Epidemics, by their nature, spill over boundaries. What my research showed time and again is that the local community works best not in isolation, but when it is supported—and curbed—by other institutions. As the sad story of Eyam’s famous “plague quarantine” shows, a community cannot go it alone. During the Eyam plague of 1665-6, the epidemic was prevented from spreading outwards by cutting contact with the outside world. At the boundary stone pictured below, Eyam villagers left money during the plague in exchange for outside provisions. The stone has six holes which were filled with vinegar to disinfect the money. This illustrates that a community needs the resources of the market, the coordinating power of the state, and the support of the wider society, in order to control contagion. 

Boundary stone, Eyam.

4. The state: a double-edged sword

When market failures or community limits threaten public health, we naturally look to the state. Its unique power to coerce citizens, raise taxes, and act across wide territories seems like the perfect tool for fighting a border-crossing enemy like an epidemic. My book shows that state capacity has indeed been crucial. As early as 1348, Italian city-states like Venice were appointing health boards and pioneering the social distancing measures that are still familiar to us today. Over the following centuries, states—especially at the local level—developed systems for sanitation, quarantine, and eventually, immunization. The ability to fund these measures and enforce compliance played a key role in the long-term decline in epidemic mortality. 

But the state, like every other institution, has a dark side. Historically, far more state capacity was poured into warfare than into public health, and wars have always been one of the most effective ways of spreading disease. States have also consistently falsified information about epidemics to protect trade, tax revenues, or military secrecy—from Venice concealing the plague in 1575, to the many governments that downplayed the 1918 flu. At its worst, state power can lead to authoritarian overkill, using an epidemic as a pretext to persecute minorities or impose brutal measures that provoke concealment and resistance, ultimately exacerbating the very contagion it claims to be fighting. 

The image below shows how colonial wars brought epidemic diseases that devastated Indigenous peoples with no immunity. In Tenochtitlan, then the largest city in the Americas (with a population of c. 215,000 in 1519), residents called the outbreak hueyzahuatl (“great leprosy”) and totomonaliztli (“pustules”) – almost certainly smallpox. Victims were covered in sores, unable to care for themselves, and many died from both disease and starvation as the epidemic disrupted food supplies.

Aztec depiction of smallpox victims in Tenochtitlan, Mexico.

What, then, makes for an effective state response? My findings suggest it is not simply a matter of fiscal capacity, centralized government, or even parliaments. The states that succeeded were those that worked with and through a heterogeneous ecosystem of other institutions. They fostered subsidiarity, empowering local governments that were better informed about local conditions. They engaged with civil society— the aggregate of non-governmental institutions that advance the interests and desires of citizens—to inform and gain the consent of their citizens. Successful states supported the market by guaranteeing property rights and contract enforcement, but regulated the negative externalities generated by market participants who violated quarantine or spread infectious waste. A variegated framework of other institutions— markets, communities, religions, professional organisations, and families— could leverage the state’s strengths and curb its darker tendencies. 

Members of the Misericordia, a voluntary lay Catholic association, caring for plague victims in Florence, 1630–31. Note the fence (right) constructed during the epidemic to separate the Misericordia from the wider city, excluding potentially infected members of the public and protecting uninfected citizens from Misericordia members who had daily contact with plague victims.

No magic pill, but a better institutional framework 

After seven centuries of evidence, from the Black Death to Covid-19, what can we say about the best way to control contagion? My conclusion is that there is no “magic pill”. No single institution—not the state, not the market, not the community—is the hero of the story. 

Instead, I found that the societies that coped best with epidemics were those with a diverse and interdependent institutional framework. A successful framework needed three key components: 

1. Institutional diversity: A rich ecosystem of different institutions, each with its own strengths, providing multiple potential solutions and preventing any one institution from becoming dangerously dominant. 
2. A well-functioning market: To generate the immense resources needed for both private and public health measures, and to spur innovation. 
3. A “temperate state”: An authority with enough capacity to solve collective-action problems (like enforcing sanitation), but that is also curbed by other institutions, preventing it from becoming unresponsive or authoritarian. 

Ultimately, societies kept ahead of epidemics by learning how to coordinate and how to innovate. This required an institutional framework that was open, flexible, and resilient. The work of economic historians and historical demographers in uncovering and understanding these deep social structures is, I believe, more critical than ever. Epidemic disease affects individual wellbeing, aggregate economic output, and societal health in the widest sense. It is by understanding the long-run history of our institutions that we can improve our modus vivendi with humans’ inseparable microbial companions. 

Further reading

• Alexander, J. T., Bubonic plague in early modern Russia: public health and disaster (2003).
• Alfani, G., Calamities and the economy in renaissance Italy: The grand tour of the horsemen of the apocalypse (2013).
• Bennett, M., War against smallpox: Edward Jenner and the global spread of vaccination (2020).
• Champion, J., Epidemic disease in London (1993).
• Cipolla, C., Public Health and the Medical Profession in the Renaissance (1976).
• Mühlhoff, K., ‘Convincing the “Herd” of immunity: Lessons from smallpox vaccination in 19th century Germany’, Economics & Human Biology 47 (2022).
  
• Pankhurst, R., The history and traditional treatment of smallpox in Ethiopia (2012).