The two ways pandemics ended through history.

Have you ever wondered how previous pandemics, plaques or epidemics ended?  Well according to historians there were only two types of endings that took place across the ages.

  1. The Medical Route – this happened when infections plummeted, either through herd immunity, changes in environment that no longer was optimum for the infection or vaccination.
  2. The Social Route – this was when the fear of the disease subsided, in other words the outbreak continued but people got tired of “panic mode” and learned to live with whichever disease was still amongst.

Let’s follow the route of three of the deadliest illnesses through history to see how or why  they “ended” … and in some cases, started and “ended” again.

“Pestilentia” – [Latin]

Yersinia pestis, a fatal infection otherwise known as the plague was the cause of three of recorded history’s deadliest pandemics.  Four to five days after falling ill, 80% of infected people would die an excruciating death.  During 541 CE the plaque spread across Europe, Asia, North Africa and Arabia killing an estimated 30 to 50 million people, perhaps half of the world’s population. Back then people had no real idea how to fight the pandemic, so how did it end?  According to Thomas Mockaitis, a history professor at DePaul University “The best guess is that the majority of people in a pandemic somehow survive, and those who survive have immunity.”

 Eight hundred years later in 1347 the plaque was back in Europe.  This time the Black Death wiped out 200 million people in 4 years.  There was no real scientific understanding of the disease, but people did realise that proximity had an impact.  In Venice sailors was held on their ships for 30 days to make sure they weren’t sick, which became known in Venetian law as a trentino.  Venetians increased the forced isolation to 40 days or a quarantino, the origin of the word quarantine.

In London the plague resurfaced roughly every 20 years from 1348 to 1665—40 outbreaks in 300 years.  And with each new plague epidemic, 20% of the men, women and children died.  The Great Plague of 1665 was the last and one of the worst of the centuries-long outbreaks, killing 100,000 Londoners in just seven months.  Eventually victims were forcibly shut into their homes and left to die, to prevent the spread of the disease.  Red crosses were painted on their doors along with a plea for forgiveness: “Lord have mercy upon us.” 

One of the worst outbreaks began in China in 1855 and spread worldwide, killing more than 12 million in India alone. Health authorities in Bombay burned whole neighbourhoods trying to rid them of the plague.

The plague never really went away.  Today it is treatable with antibiotics and some theories are that it has also evolved into a less deadly bacterium. It is feared that the plague bacterium could develop drug resistance and again become a major health threat. One case of a drug-resistant form of the bacterium was found in Madagascar in 1995. A further outbreak in Madagascar was reported in November 2014 and in October 2017 the deadliest outbreak of the plague in modern times hit Madagascar, killing 170 people and infecting thousands.

Image: A Sicilian fresco from 1445. In the previous century, the Black Death killed at least a third of Europe’s population. Credit…Werner Forman/Universal Images Group/Getty Images

The Red Plague

The first credible evidence of smallpox is found in Egyptian mummies from 3000 years back.  Smallpox was endemic to Europe, Asia and Arabia for centuries, killing three out of ten people it infected.  During the 18th century the disease killed an estimated 400,000 Europeans each year and was responsible for a third of all blindness.  Between 20% and 60% of all those infected—and over 80% of infected children—died from the disease.

During the 20th century, it is estimated that smallpox was responsible for 300–500 million deaths.  In the early 1950s an estimated 50 million cases of smallpox occurred in the world each year.  As recently as 1967, the World Health Organization estimated that 15 million people contracted the disease and that 2 million died in that year.

When Europeans arrived in “The New World” in the 15th century, the indigenous peoples had zero natural immunity to smallpox and the virus cut them down by the tens of millions.  In the Americas smallpox wiped out 90 to 95% of the indigenous population over a century.  Mexico went from 11 million people pre-conquest to one million.  Smallpox had the same horrific outcome for indigenous people of Australia and Africa. The elephant war circa AD 568 is probably the earliest record of smallpox in Africa.  After fighting a siege in Mecca, Ethiopian troops contracted the disease which they carried back to Africa.  Sub-Saharan outbreaks can be traced back to 1484 in Angola, wiping out 25 000 inhabitants in the 1864 epidemic.  An Indian ship docked in Cape Town in 1713 and it is speculated that smallpox was brought ashore with dirty laundry.    Many of the settler European population suffered, and whole clans of the Khoisan people were wiped out.

Only in 1796 did Edward Jenner discover the smallpox vaccine. Efforts to protect populations against smallpox by way of vaccination followed for centuries after, but only in 1979 did the WHO certify the global eradication of smallpox – it took 200 years. 

Measure of how many people each sick person will infect part of the reason smallpox was so deadly.

Grippe – [French;1837]

Influenza, commonly known as the flu, is an infectious disease of birds and mammals.  Through the ages it was thought to be caused by comets, earthquakes, volcanoes, cosmic dust, the rising or setting of the sun, vapors arising from the air and ground, or a blast from the stars – now we know that it is caused by an RNA virus of the family Orthomyxoviridae.

As we are now all well aware, an influenza pandemic is an epidemic of an influenza virus that spreads across a large region (either multiple continents or worldwide) and infects a large proportion of the population.  In contrast to the regular seasonal epidemics of influenza, these pandemics occur irregularly.  The normal seasonal flu kills between 250 000 and 500 000 people every year, and has claimed between 340 million and 1 billion human lives throughout recorded history. 

Although Hippocrates described the symptoms of human influenza in 400BC it is only in 1357 that the term influenza is first used to describe “a disease prevailing”.  The first reliable and well documented, influenza pandemic started in 1557 and spread from Asia to the Ottoman Empire, then Europe, the Americas, and Africa.  It was during this pandemic that the flu received its first English name and was linked to miscarriages. It lasted for 2 years. 

 Avian Influenza, normally found in birds was first transmitted to humans in 1889 and caused what was known as the Fowl plague.

There have been five influenza pandemics during the last 140 years, with the 1918 Spanish flu pandemic being the worst; The Spanish flu (H1N1), infected an estimated 500 million people across the globe and claimed between 50 and 100 million lives. This pandemic would be described as “the greatest medical holocaust in history” and is estimated to have killed in a single year more people than the Black Death bubonic plague killed in four years from 1347 to 1351. 

In 1957 a new, virulent influenza virus, subtype H2N2 broke out in Guizhou (China), and spread to the neighbouring Yunnan and Hunan provinces. It turned into a pandemic and killed 1 to 4 million people. The 2009 H1N1 pandemic affected 74 countries and resulted in 18 500 deaths.

The first real flu vaccines were only made in 1940, which begs the question; how did most of these pandemics end? Historians point out that a social ending occurred first.  In the wake of WWI and the economic depression that followed, the collective mind-set changed from fear to future-orientated. Academics agree that the medical end of the Spanish flu pandemic occurred in 1920, when society ended up developing a collective immunity to it, although the virus never completely disappeared.  The Spanish flu continued to appear, mutating and acquiring genetic material from other viruses. For example, the 2009 flu had genetic elements from earlier viruses, so older individuals were better protected than the young.  This also occurred with the Spanish flu, with those over the age of 30 having better survival rates.   It is speculated this is because the older generation lived with the so-called Russian flu in 1889 and 1890. 

So how is our current Covid-19 pandemic likely to end? 

Today various influenza vaccines have been developed.  The most common human vaccine is the trivalent influenza vaccine that contains purified and inactivated material from three viral strains. A vaccine formulated for one year may be ineffective in the following year, since the influenza virus changes rapidly over time and different strains become dominant.  

Epidemiologist and evolutionary biologist Sarah Cobey, of the University of Chicago says: “This coronavirus is unprecedented in the combination of its easy transmissibility, a range of symptoms going from none at all to deadly, and the extent that it has disrupted the world. A highly susceptible population led to near exponential growth in cases. This is a distinct and very new situation.”

It seems the common agreement among scientists is that both the social and medical routes will play an important part.   Researchers have banded together like never before and are working on multiple fronts to develop remedies.  But even if a vaccine is developed, unless it is administered to all of the world’s eight billion inhabitants who are not currently sick or recovered, COVID-19 will circulate and make people sick seasonally.  The combination of vaccination and natural immunity will protect many of us, but like most viruses the Corona virus will live on.  The huge socio-economic impact due to Government lock-downs will play an equally big part in “ending” the pandemic.   Most people will probably get-on with life regardless of vaccines as the basic need for survival will outweigh the fear of Covid-19.

It truly seems like the more things change, the more they stay the same.

Visualization of the history of pandemics. Size of the balls indicate the relative size of death during each.

Published by Adéle

My career started in journalism late 80's and although I've spent the past two decades working in the marketing and business management fields, my love of political science, human behavior and current affairs never diminished. With "spare time" on hand during the global Covid-19 lock-down ... well a natural progression ... build a website (marketing) and write (journalism) about current happenings (passionate about specifically human rights). Covid-19 also saw the start of Local Savers a business borne from necessity that is growing continuously. Local Savers are committed to offering quality bulk food and related products at the best prices possible.

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