The Plague of Justinian (541 - 750 AD) brought trade to a standstill and weakened the Byzantine, or Eastern Roman, Empire, led by Justinian I. Historians estimate that it killed about half the world's population while setting back Justinian's military efforts. As he was attempting to reunite the Western and Eastern halves of the Roman Empire at the time, this pandemic was another player in its centuries-long decline and fall.
The bubonic plague, or "Black Death" (1347 - 1351), killed so many people — historians estimate 60% of Europe's population died, nevermind Asia — that living standards actually improved for the survivors. There was greater upward mobility afterward and some historians consider it the beginning of serfdom's long decline. It was also a turning point in the intensification of European prejudice and bigotry against minorities, particularly Jews and Roma.
Smallpox (15th - 17th centuries) paved the way for the colonization of the Americas, killing as much as 95% of the native population, largely before Europeans began their conquest. The mineral wealth exploited from the "New World" in the form of gold and silver led to massive inflation in the Spanish Empire and the resulting "price revolution" changed how money was valued, a crucial moment in the development of modern capitalism.
The Cholera pandemic (1817 - 1823) at first illustrated the importance of modern sanitation, given its transmission through contaminated food or water. As it has persisted in less-developed countries and become the world's longest-running pandemic, cholera highlights the dire consequences of wealth inequality. It still affects millions today, skewed largely toward countries with lack of social development.
After the Spanish Flu (1918 - 1919) died down, significant research went into understanding how it broke out, helping to lessen the impact of subsequent outbreaks. It infected about 500 million people and killed about 50 million people globally. But governments at the time downplayed or even denied its seriousness, with its name coming from the fact that Spain was one of the few to acknowledge it. Some modern governments have responded to the coronavirus with similar downplaying or denials.
The "Hong Kong Flu" or H3N2 (1968 - 1970) highlighted the importance of vaccines and the important role they play in containing diseases. It was an exceptionally contagious pandemic, as 500,000 became infected within two weeks of the first outbreak.
HIV/AIDS, which first broke out in the 1980s, continues to impact the lives of people today and the negative influence of disease on the global economy is still being studied. It had a massive social impact, as the global LGBTQ community became vocal and visible in unprecedented ways because of the disproportionate impact on its members.
The SARS (2002 - 2003) outbreak increased awareness about preventing viral disease transmission, particularly in Hong Kong, where public surfaces have been regularly sanitized since and facemasks have become a common sight.
A major legacy of the Swine Flu (2009 - 2010) may have been how it exposed the persistent vulnerability of many countries with advanced healthcare systems to a fast-moving, flu-like outbreak. Now that the coronavirus has created a socially distanced world, Swine Flu stands out as a pandemic that didn't change the world — but probably should have.
Ebola, which began in 2014, is estimated to have cost a total of $4.3 billion, with inbound investments dramatically dropping in Guinea, Liberia, and Sierra Leone.
Coronavirus or COVID-19 (2019 - present) has pushed the world towards a recession, as its largely uncontained spread prompted governments to encourage social distancing in an attempt to limit infection. By March, the American economy saw record levels of unemployment and a plummeting stock market. It also resulted in an unprecedented number of people working from home indefinitely, with untold ramifications for the future of office life.