The most recent Journal of Economic Literature includes four essays on how historical epidemics and pandemics affected major macroeconomic variables. Together, they account for 170-someodd pages, which I will summarize below. Each of them is a detailed literature review on decades of historical research. While they are dense, they are for the most part readable. Part 2 will summarize three articles from The Journal of Economic Perspectives on Macro Policy in the Pandemic.

“Modern Infectious Diseases: Macroeconomic Impacts and Policy Responses” – D. Bloom, M. Kuhn, and K. Prettner The greatest strength of this paper is in critically discussing the various methodologies and theories we have available to even answer the question of how epidemics affect the economy. This is aside from the problem that “narrow economic considerations take inadequate account of the ethical, normative, and political dimensions of decisions that relate to saving lives.”

Generally, micro-based methods that focus on the impacts on individuals and add them up ignore indirect, complex interactions that macro-based methods do capture. For instance, increasing the probability that a 15 year old survives to age 60 by 10 percentage points (roughly equivalent to moving from India to China) increases labor productivity by 9.1 percent. On the other hand, most macro models miss behavioral responses are an insufficiently complex. One problem is that my individual incentive to take preventative actions depends on everyone else. This is something I noticed in my own life – here in Texas where almost no one wore a mask, I had a strong incentive to stay masked myself; when we traveled to any state west of us, almost everyone was masked and surfaces were regularly cleaned, so I felt much less urgency to wear a mask myself. Their conclusion is that diseases will be difficult to eradicate via “private actions alone.” They therefore conclude that some form of government lockdown is likely to be warranted.

Epidemics will have different impacts on the economy depending on a) disease-specific characteristics (how much do they impact working-age population, how much long-term damage do they do, etc) b) population characteristics, particularly how much poverty there is and c) country characteristics, particularly government capacity. Because of this, the same epidemic might have minor impacts in one country, create a poverty trap in a second, impose economic hardship in a third while leaving long-run health mostly untouched, or leaving the economy mostly unaffected but harming health and increasing the incidence of other diseases in a fourth.

“Epidemics, Inequality, and Poverty in Preindustrial and Early Industrial Times” – G. Alfani Most important point: epidemics reduce poverty by either a) changing society/laws/markets in ways that are pro-poor and b) killing more poor people than other socioeconomic groups. If a particular disease leads more to the latter, then there will be very small impacts of disease on poverty. Standard intermediate macroeconomics says that wages come from productivity and the more land or physical capital each worker has, the higher their wages will be. Because of this, the usual story I tell my students about the Black Death that killed off 20-35% of western Europe but left the capital alone is that it raised wages for the poorest and created a large middle class, setting the stage for the Renaissance. Alfani shows Gini coefficients [measures of inequality] falling by 30 percent or more.

But this didn’t happen everywhere. “Government intervention may have suppressed wage bargaining for an extended period of time” in post-Colombus Mexico (Scheidel 2017), or Black-Death-era Spain (Álvarez-Nodal and Prados de la Escosura, 2013), and Poland.

And it didn’t happen always. Repeated epidemics in the 17th century that were as deadly as the Black Death in some communities didn’t seem to reduce inequality at all, either in total or compared to what happened in communities that were unaffected. Why not? One difference is that when epidemics happened more often, governments changed inheritance rules to ensure large amounts of wealth stayed controlled by only a few. He also argues that demand for labor will decrease, and if it decreases as much as the labor supply, wages may not increase at all. On top of these effects, I infer from his paper that later epidemics killed a higher percent of skilled workers than the Black Death did, and that stunted any change in the skill premium. Then there are diseases like cholera that not only hit poor areas hardest, but tended to increase and concentrate the negative aspects of poverty.

Alfani and Murphy (2017): “From the fifteenth century, most plagues were particularly harsh on the poor. This has to do both with the poor’s relatively unhealthy living areas, but also with how they were treated during the epidemics. Once doctors and health authorities noticed that plague mortality tended to be higher in the poorest parts of the city, they began to see the poor themselves as the potential culprits of the spread of the infection.” That attitude is contrasted with efforts to improve sanitation and nutrition to both reduce disease and improve the lives of the poor.

“The 1918 Influenza Pandemic and Its Lessons for COVID-19” – B. Beach, K. Clay, and M. Saavedra “The first lesson from 1918 is that the health effects were large and diffuse” and we may never know just how large because of inaccurate record keeping, “issues that also undermine our ability to quantify the impact of COVID-19.” The second lesson: The Spanish flu epidemic was more likely to kill working-age adults, so it had a major long-run labor supply shock which COVID is unlikely to cause, even though both have caused recessions.

Among the differences between the two are that epidemics were not unusual in 1918 and it happened right at the end of World War I, which had upset many economies already and led to falling productivity for reasons unrelated to the pandemic. We have also documented a wide range of negative health impacts from the 1918 epidemic and are only beginning to document the longer-term impacts of COVID, which will have to be studied in the future.

Interestingly, while there was some attempt at social distancing and closing society down in 1918, it was much shorter-lived and not as severe as what we tried during COVID. While they were “somewhat effective at reducing mortality in 1918, … the extent to which more restrictive [regulations] would have further reduced pandemic mortality remains debated.”

“The Economic Impact of the Black Death” – R. Jedwab, N. Johnson, and M. Koyama There are three primary lenses through which economists have viewed the Black Death. Malthusians argue that smaller populations increase wages (by raising the capital/labor or land/labor ratios) and lower inequality. The “Smithian” view is that larger populations are necessary for a greater division of labor, specialization, and larger markets that support important technologies. The third strand focuses on the role of institutions, both as causes and effects.

“In the very short run [the Black Death] caused a breakdown in markets and economic activity more generally.” In a longer run sense, though, England, Spain, and Italy had very different divergences between wages and productivity. Put another way, England had larger Smithian effects than Spain or Italy and Italy had the largest Malthusian effects. Thus, rather than one model being “right” and the other “wrong,” there is more of a continuum, moderated in part by institutions.

In the years after the plague, people moved out of rural areas to the cities that had been hardest hit because wages had increased more there, which also increased reforestation. In Western Europe, workers’ bargaining power increased, eroding the institution of serfdom. Craft guilds increased dramatically, though their net effect is questionable – decreasing competition through monopoly power but increasing human capital accumulation through apprenticeships. States grew in size and influence, perhaps because there were fewer people to oppose them, with growing taxation accompanying investment in public health and the ability to impose quarantines.