Healthcare
Visualizing the History of Pandemics
The History of Pandemics
Pan·dem·ic /panˈdemik/ (of a disease) prevalent over a whole country or the world.
As humans have spread across the world, so have infectious diseases. Even in this modern era, outbreaks are nearly constant, though not every outbreak reaches pandemic level as COVID-19 has.
Today’s visualization outlines some of history’s most deadly pandemics, from the Antonine Plague to the current COVID-19 event.
A Timeline of Historical Pandemics
Disease and illnesses have plagued humanity since the earliest days, our mortal flaw. However, it was not until the marked shift to agrarian communities that the scale and spread of these diseases increased dramatically.
Widespread trade created new opportunities for human and animal interactions that sped up such epidemics. Malaria, tuberculosis, leprosy, influenza, smallpox, and others first appeared during these early years.
The more civilized humans became – with larger cities, more exotic trade routes, and increased contact with different populations of people, animals, and ecosystems – the more likely pandemics would occur.
Here are some of the major pandemics that have occurred over time:
Name | Time period | Type / Pre-human host | Death toll |
---|---|---|---|
Antonine Plague | 165-180 | Believed to be either smallpox or measles | 5M |
Japanese smallpox epidemic | 735-737 | Variola major virus | 1M |
Plague of Justinian | 541-542 | Yersinia pestis bacteria / Rats, fleas | 30-50M |
Black Death | 1347-1351 | Yersinia pestis bacteria / Rats, fleas | 200M |
New World Smallpox Outbreak | 1520 – onwards | Variola major virus | 56M |
Great Plague of London | 1665 | Yersinia pestis bacteria / Rats, fleas | 100,000 |
Italian plague | 1629-1631 | Yersinia pestis bacteria / Rats, fleas | 1M |
Cholera Pandemics 1-6 | 1817-1923 | V. cholerae bacteria | 1M+ |
Third Plague | 1885 | Yersinia pestis bacteria / Rats, fleas | 12M (China and India) |
Yellow Fever | Late 1800s | Virus / Mosquitoes | 100,000-150,000 (U.S.) |
Russian Flu | 1889-1890 | Believed to be H2N2 (avian origin) | 1M |
Spanish Flu | 1918-1919 | H1N1 virus / Pigs | 40-50M |
Asian Flu | 1957-1958 | H2N2 virus | 1.1M |
Hong Kong Flu | 1968-1970 | H3N2 virus | 1M |
HIV/AIDS | 1981-present | Virus / Chimpanzees | 25-35M |
Swine Flu | 2009-2010 | H1N1 virus / Pigs | 200,000 |
SARS | 2002-2003 | Coronavirus / Bats, Civets | 770 |
Ebola | 2014-2016 | Ebolavirus / Wild animals | 11,000 |
MERS | 2015-Present | Coronavirus / Bats, camels | 850 |
COVID-19 | 2019-Present | Coronavirus – Unknown (possibly pangolins) | 6.9M (Johns Hopkins University estimate as of March 1, 2023) |
Note: Many of the death toll numbers listed above are best estimates based on available research. Some, such as the Plague of Justinian and Swine Flu, are subject to debate based on new evidence.
Despite the persistence of disease and pandemics throughout history, there’s one consistent trend over time – a gradual reduction in the death rate. Healthcare improvements and understanding the factors that incubate pandemics have been powerful tools in mitigating their impact.
March 1, 2023 Update: Due to popular request, we’ve also visualized how the death tolls of each pandemic stack up as a share of total estimated global populations at the time.
Wrath of the Gods
In many ancient societies, people believed that spirits and gods inflicted disease and destruction upon those that deserved their wrath. This unscientific perception often led to disastrous responses that resulted in the deaths of thousands, if not millions.
In the case of Justinian’s plague, the Byzantine historian Procopius of Caesarea traced the origins of the plague (the Yersinia pestis bacteria) to China and northeast India, via land and sea trade routes to Egypt where it entered the Byzantine Empire through Mediterranean ports.
Despite his apparent knowledge of the role geography and trade played in this spread, Procopius laid blame for the outbreak on the Emperor Justinian, declaring him to be either a devil, or invoking God’s punishment for his evil ways. Some historians found that this event could have dashed Emperor Justinian’s efforts to reunite the Western and Eastern remnants of the Roman Empire, and marked the beginning of the Dark Ages.
Luckily, humanity’s understanding of the causes of disease has improved, and this is resulting in a drastic improvement in the response to modern pandemics, albeit slow and incomplete.
Importing Disease
The practice of quarantine began during the 14th century, in an effort to protect coastal cities from plague epidemics. Cautious port authorities required ships arriving in Venice from infected ports to sit at anchor for 40 days before landing — the origin of the word quarantine from the Italian “quaranta giorni”, or 40 days.
One of the first instances of relying on geography and statistical analysis was in mid-19th century London, during a cholera outbreak. In 1854, Dr. John Snow came to the conclusion that cholera was spreading via tainted water and decided to display neighborhood mortality data directly on a map. This method revealed a cluster of cases around a specific pump from which people were drawing their water from.
While the interactions created through trade and urban life play a pivotal role, it is also the virulent nature of particular diseases that indicate the trajectory of a pandemic.
Tracking Infectiousness
Scientists use a basic measure to track the infectiousness of a disease called the reproduction number — also known as R0 or “R naught.” This number tells us how many susceptible people, on average, each sick person will in turn infect.
Measles tops the list, being the most contagious with a R0 range of 12-18. This means a single person can infect, on average, 12 to 18 people in an unvaccinated population.
While measles may be the most virulent, vaccination efforts and herd immunity can curb its spread. The more people are immune to a disease, the less likely it is to proliferate, making vaccinations critical to prevent the resurgence of known and treatable diseases.
It’s hard to calculate and forecast the true impact of COVID-19, as the outbreak is still ongoing and researchers are still learning about this new form of coronavirus.
Urbanization and the Spread of Disease
We arrive at where we began, with rising global connections and interactions as a driving force behind pandemics. From small hunting and gathering tribes to the metropolis, humanity’s reliance on one another has also sparked opportunities for disease to spread.
Urbanization in the developing world is bringing more and more rural residents into denser neighborhoods, while population increases are putting greater pressure on the environment. At the same time, passenger air traffic nearly doubled in the past decade. These macro trends are having a profound impact on the spread of infectious disease.
As organizations and governments around the world ask for citizens to practice social distancing to help reduce the rate of infection, the digital world is allowing people to maintain connections and commerce like never before.
Editor’s Note: The COVID-19 pandemic is in its early stages and it is obviously impossible to predict its future impact. This post and infographic are meant to provide historical context, and we will continue to update it as time goes on to maintain its accuracy.
Update (March 1, 2023): We’ve adjusted the death toll for COVID-19, and will continue to update on a regular basis.
population
Charted: The Rapid Decline of Global Birth Rates
For the last 70 years, birth rates for the 49 most populous countries of the world have fallen sharply, heralding an uncertain future.
Charted: The Rapid Decline in Global Birth Rates
In 1798, British economist Thomas Malthus proposed a groundbreaking theory now known as the “Malthusian Trap”—suggesting that human population growth is exponential and thus would outpace the linear growth of resources such as food supply.
He worried that this runaway population growth would become unsustainable, eventually relying on sudden shock events—wars, disasters, famines—to reset the population to more sustainable levels. And over the next 200 years, the world population skyrocketed from 1 billion to 8 billion people on the planet.
However, as it turns out, no such shock events were required to turn the tide of population growth. Instead, it’s been rapidly declining birth rates across the world that seem to be leading to an unthinkable outcome for Malthus: a gradually plateauing or even shrinking global population.
In the visualization above, Pablo Alvarez has visualized the crude birth rate for the 49 most populous countries of the world in 2021, using data from the UN’s World Population Prospects 2022 to examine changes since 1950.
Understanding Birth Rates vs Fertility Rates
Birth rates are commonly measured using a metric called the “crude birth rate” (CBR), which represents the number of live births per 1,000 individuals in a given population during a specific period—usually one year.
The measured decline in CBR is also a result of plummeting fertility rates across the globe. Not to be confused with birth rates, fertility rates measure how many children a woman will have over the course of her lifetime.
While a country’s birth rate is directly impacted by the fertility rate, it also takes into account other factors: population size, age structure of the population, access to contraception, cultural norms, government policies, and socioeconomic conditions.
Birth Rates of the Most Populated Countries
Here’s a snapshot of the CBR for the 49 most populous countries of the world at different years from 1950 to 2021.
Country | 1950 | 1990 | 2021 | % Change (1950-2021) |
---|---|---|---|---|
🇦🇫 Afghanistan | 48.87 | 51.42 | 35.84 | -27% |
🇩🇿 Algeria | 51.05 | 30.76 | 21.52 | -58% |
🇦🇴 Angola | 46.15 | 51.34 | 38.81 | -16% |
🇦🇷 Argentina | 26.00 | 21.99 | 13.90 | -47% |
🇧🇩 Bangladesh | 46.52 | 34.97 | 17.82 | -62% |
🇧🇷 Brazil | 46.43 | 24.84 | 12.88 | -72% |
🇨🇦 Canada | 26.80 | 15.46 | 9.82 | -63% |
🇨🇳 China | 41.05 | 24.44 | 7.63 | -81% |
🇨🇴 Colombia | 46.74 | 27.37 | 14.20 | -70% |
🇨🇩 DRC | 46.02 | 46.01 | 42.05 | -9% |
🇪🇬 Egypt | 54.20 | 33.21 | 22.56 | -58% |
🇪🇹 Ethiopia | 49.40 | 50.05 | 32.38 | -34% |
🇫🇷 France | 20.77 | 13.34 | 10.50 | -49% |
🇩🇪 Germany | 16.22 | 11.30 | 9.17 | -43% |
🇬🇭 Ghana | 46.76 | 40.37 | 27.55 | -41% |
🇮🇳 India | 43.84 | 31.82 | 16.42 | -63% |
🇮🇩 Indonesia | 40.64 | 25.52 | 16.42 | -60% |
🇮🇷 Iran | 50.14 | 32.46 | 13.70 | -73% |
🇮🇶 Iraq | 45.73 | 39.41 | 27.37 | -40% |
🇮🇹 Italy | 19.70 | 10.01 | 6.93 | -65% |
🇯🇵 Japan | 28.34 | 9.91 | 6.57 | -77% |
🇰🇪 Kenya | 49.47 | 43.52 | 27.68 | -44% |
🇲🇾 Malaysia | 44.31 | 27.89 | 15.24 | -66% |
🇲🇽 Mexico | 49.31 | 29.30 | 14.86 | -70% |
🇲🇦 Morocco | 51.08 | 29.23 | 17.55 | -66% |
🇲🇿 Mozambique | 46.66 | 46.38 | 36.60 | -22% |
🇲🇲 Myanmar | 45.58 | 27.48 | 17.10 | -62% |
🇳🇵 Nepal | 47.06 | 38.11 | 20.40 | -57% |
🇳🇬 Nigeria | 45.61 | 43.79 | 37.12 | -19% |
🇵🇰 Pakistan | 43.72 | 43.15 | 27.52 | -37% |
🇵🇪 Peru | 48.16 | 30.90 | 17.62 | -63% |
🇵🇭 Philippines | 49.84 | 33.26 | 21.81 | -56% |
🇵🇱 Poland | 30.85 | 14.28 | 9.49 | -69% |
🇷🇺 Russia | 28.80 | 13.52 | 9.64 | -67% |
🇸🇦 Saudi Arabia | 53.34 | 34.41 | 17.47 | -67% |
🇿🇦 South Africa | 41.65 | 31.15 | 19.82 | -52% |
🇰🇷 South Korea | 40.03 | 15.69 | 5.58 | -86% |
🇪🇸 Spain | 20.01 | 10.30 | 7.55 | -62% |
🇸🇩 Sudan | 47.75 | 43.09 | 33.60 | -30% |
🇹🇿 Tanzania | 47.75 | 43.78 | 36.21 | -24% |
🇹🇭 Thailand | 43.84 | 19.73 | 9.00 | -79% |
🇹🇷 Türkiye | 46.39 | 25.87 | 14.68 | -68% |
🇺🇸 U.S. | 22.81 | 16.73 | 11.06 | -52% |
🇺🇬 Uganda | 52.42 | 51.37 | 36.80 | -30% |
🇬🇧 UK | 16.44 | 13.88 | 10.08 | -39% |
🇺🇦 Ukraine | 22.95 | 12.76 | 7.72 | -66% |
🇺🇿 Uzbekistan | 39.85 | 33.98 | 23.55 | -41% |
🇻🇳 Vietnam | 38.82 | 28.51 | 15.01 | -61% |
🇾🇪 Yemen | 52.59 | 50.64 | 30.54 | -42% |
Every country on the list has seen a decline in birth rates in the last 70 years, with some declines more staggering than others. For example, China recorded 41 births per 1,000 people in 1950. By 2021, that number had fallen to just 7.6, a 81% decrease.
South Korea, the 29th most populous country in the world in 2021, saw an even larger 86% drop in its birth rate since 1950. In fact, almost every single country in this dataset has seen a double-digit fall in their birth rates over the past 70 years. Only the Democratic Republic of Congo has seen a single-digit percentage decline between 1950 and 2021.
Why are Global Birth Rates Falling?
For the 49 most populated countries in 2021, birth rates have halved on average in the last 70 years:
49 Most Populated Countries | 1950 | 1990 | 2021 |
---|---|---|---|
Average Birth Rate | 40.99 | 30.18 | 19.50 |
Median Birth Rate | 45.73 | 30.76 | 17.10 |
But while the thought of a shrinking world population may seem worrisome, declining birth rates are generally thought of as a triumph of rapid socio-economic development.
As countries progress and living standards improve, there is a shift in societal norms and aspirations. For example, expanded education and career opportunities for women allow the pursuit of professional growth and personal goals, with some women choosing to delay starting a family or having smaller families.
Growing urbanization is another key driver of declining birth rates, characterized by smaller living spaces, increased focus on careers, and limited support networks. Another is the growing access to family planning services and contraceptives, particularly since the 1970s.
What are the Future Consequences?
The biggest consequence of declining birth rates—and one that is already being seen in many parts of the world—is a rapidly aging population.
With fewer children being born, the proportion of elderly individuals increases relative to the working-age population. This demographic imbalance poses challenges for social welfare systems, healthcare, and pension schemes.
Declining birth rates can also impact the labor market and economic productivity. A smaller workforce may lead to labor shortages, skill gaps, and reduced innovation. And shrinking populations reduce consumer demand, a cornerstone of the global economy, which may trigger a restructure of the current growth model of development.
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