Pandemics: agents of global change

It was the early 1990s, while working at the American College of Physicians in Philadelphia, I became interested in epidemiology. With all the doctors around (there were twelve different medical sub-specialties at ACP), it was not hard to be impressed with their serious demeanor about medicine but more important – their extraordinary knowledge. Some years later, I found myself studying medical anthropology and epidemiology in California. One area that fascinated me was infectious diseases and particularly the bubonic plague and the devastating impact it had on just about everything during the 14th century. Also, I was concerned with how it took centuries for the world to return to normal. Even more important, I was amazed at how the plague changed the balance of power in the world socioeconomically and the role the disease played in effecting that change.

Generations of scholars have attempted to understand more clearly the cultural, social and economic impacts of pandemics. When confronting the complexities of these events, many found that not only do they inflict demographic carnage but also cause long-lasting and sometimes permanent changes to socioeconomic institutions and critical infrastructures in countries around the world. The possibility of another worldwide influenza pandemic is a grave concern. There are a number of research studies, reports, and lectures concerning the impact of another worldwide influenza pandemic and the catastrophic effects it could cause to human life and economic stability. In 2005, for example, the World Bank estimated that a global influenza pandemic would cost the world economy an estimated $800 billion and kill tens of millions of people. Research conducted by the U.S. Centers for Disease Control and Prevention estimated deaths could reach 207,000 and cost to the U.S. economy in the range of $166 billion. While the U.S. Department of Health and Human Services estimated up to 1.9 million deaths and nearly $200 billion in economic costs could be the result of another outbreak. In almost all case studies concerning pandemics, many of the scenarios are based on the global influenza pandemic of 1918 (the Spanish flu pandemic) and the historic Black Death (magna pestilencia) of 1347-1351 that killed about 60 million people. The almost unlimited number of comparisons and analyses tend to focus on two major areas – the demographic and economic consequences. However, it is important to understand that in the case of the Spanish flu pandemic, there is more data available on pandemic mortalities than economic data, and in the case of the Black Death, systematic evidence is limited to governmental documents, ecclesiastical records, and commercial archives. It is likely that the absence of data is one reason for some of the scarcity of research on the subject but for the most part, the demographic and economic similarities of these two pandemics can provide some insight into the effects of pandemics as agents of global change. The point here is that for at least two decades, scientists, researchers, medical professionals, journalists, and some very astute business professionals knew another pandemic was heading our way.

Given the importance of modeling to infectious disease research, the Spanish flu pandemic is critically important when making comparisons between the bubonic pandemic historically and as a model for future infectious disease outbreaks. Although there is limited data available, these two events can be useful in making reasonable inferences concerning the consequences of a modern-day pandemic.

In describing the structure and rate of mortality, the Spanish pandemic of 1918 had three distinct waves beginning in March 1918 and continuing throughout the spring of 1919. The most devastating waves were the second (fall of 1918) and the third (Spring of 1919). The pandemic’s impact was most devastating to the states of Pennsylvania, Maryland, and Colorado with the highest mortality rates. As the disease moved westward, some cities were able to minimize the impact by taking precautions such as closing schools, churches, and limiting commercial activities essentially self-quarantining and practicing social distancing. Under normal circumstances, mortality rates from a typical influenza season are highest among the very young and the very old. But the Spanish pandemic showed mortality rates highest among the population aged 18 through 40 and more for males than females. Also, individuals with the strongest immune systems were more likely to die than individuals with weaker immune systems. Even more striking, the fact that males in the 18 – 40 age category that were hardest hit by the disease caused serious economic consequences for families. This was due to the loss of the primary wage earner in families. More indirectly, these consequences impacted many businesses.

With the Black Death, the most significant factor impacting demographic and economic consequences was several recurrences of the disease over a longer period of time. For example, England over the period of 1351 to 1485, considering both local and national recurrences, endured thirty years of the plague. Also, Hamburg, Cologne, Nuremberg, and Perugia were hit nineteen times each in the fifteenth century. During the second plague (pestis secunda) of 1361 – 1362, recurrences were ten to twenty percent less, and ten to fifteen percent less during the third plague (pestis tertia) of 1369. The Black Death’s persistence is viewed as a reason for a slower demographic recovery and deeper socioeconomic consequences. It is worth stressing that the plague seemed to have a preference for urban over rural, men over women, poor over affluent and young over-mature in its demographic selection. In fact, during the second plague, eyewitnesses reported that the disease’s preference for young over older adults caused it to become known as the Children’s Plague (pestis puerorum mortalité des enfants). Further, the catastrophic demographic shift caused by the plague rippled through the agrarian economy devastating productivity, cultivation, and exacerbating an already existing imbalance between population and food supply. In the aftermath, landed gentry and peasants attempted to readjust to the economic consequences of a smaller agricultural labor pool. Before the plague, the economic advantage belonged to the landed gentry in terms of a rising population. This made it possible for lords to keep wages low, and rents and prices high. However, the plague swung the advantage in favor of the peasant. In fact, the rural worker was able to demand and receive higher wages. For example, wages in England rose from twenty to twenty-eight percent during the decade of the 1340s to 1350s and twenty to forty percent from the 1340s to the 1360s. Another economic change resulting from all this was the increases in the supply of gold and silver on a per capita basis which unleashed substantial inflation in prices. More importantly, this inflation reduced the purchasing power of the peasant to the extent that even with higher wages, his earnings bought him no more and often significantly less than before the plague. Similarly, cities and states having greater mortality rates during the Spanish flu pandemic experienced an increase in manufacturing wage growth over the period 1914 through 1919. Studies show that mortality rates had a direct impact on wages in the manufacturing sector in U.S. cities and states during and immediately following the outbreak. Also, the reduction in manufacturing labor supply, in addition to increasing the marginal product of labor and capital per worker led to increases in real wages for workers. Apparently, states with higher mortality rates had a greater increase in capital per worker and higher incomes after the pandemic.

For the most part, then, lessons in terms of a modern-day pandemic based on research conducted on these two pandemics show an extremely severe impact in billions of dollars lost and hundreds of thousands or even millions of lost lives. Research shows that cities are likely to have more deaths than rural areas; low-income groups will have a greater chance of death because the majority of low-income groups live in urban areas; depending on the duration and severity of the outbreak, health care system facilities may be overwhelmed; local quarantines would likely hurt businesses – employees would be laid off, and small businesses could suffer huge revenue losses. Perhaps one of the most important impacts is a severe interruption to critical infrastructure operations such as gas and electricity, food and water supply chains, transportation and communications. These services depend upon a workforce and if a workforce succumbs to illness –  there are huge vulnerabilities. The larger point is that a modern-day pandemic could possibly be more severe and virulent than the Spanish flu pandemic of 1918.


Brahmbhatt, Milan. (Sept. 23, 2005) “Avian Influenza: Economic and Social Impacts.” Speech. World Bank, Washington, D.C.; Meltzer, M.; Cox, N.; and Fukunda, K. (1999). “The Economic Impact of Pandemic Influenza in the United States: Priorities for Intervention.” Emerging Infectious Diseases, 5(5): 659-671.; U.S. Department of Health and Human Services. (2005). “HHS Pandemic Influenza Plan.” Washington, D.C.; Barry, John M. (2004). The Great Influenza: The Epic Story of the Deadliest Plague in History. Penguin Group, New York; Crosby.; Alfred W. (2003). America’s Forgotten Pandemic: The Influenza of 1918. Cambridge University Press, Cambridge UK.; U.S. Census Bureau. Income, Poverty, and Health Insurance Coverage in the United States: 2005, Table (; Crosby, Alfred W. (2003). America’s Forgotten Pandemic: The Influenza of 1918. Cambridge University Press, Cambridge, page 82.; Grant, T. A. (2007). Economic Effects of the 1918 Influenza Pandemic: Implications for a Modern-day Pandemic. St. Louis: Federal Reserve Bank of St. Louis