Pandemics That Changed History

Analysis by Dr. Joseph Mercola Fact Checked


Story at-a-glance -

  • From the plague to smallpox to the AIDS epidemic of the 1980s, the world has overcome many overwhelming pandemics
  • The World Health Organization has declared coronavirus a pandemic but also a "pandemic that can be controlled"
  • When plague was found to be caused by the Yersinia pestis bacterium from rat fleas, treatment became possible
  • Smallpox was eradicated after public health measures like isolation and sanitation were introduced

Coronavirus (COVID-19) has been ruled a pandemic by the World Health Organization (WHO).1 "Pandemic is not a word to use lightly or carelessly," said WHO director-general Tedros Adhanom, in his opening remarks at a media briefing about coronavirus.

"It is a word that, if misused, can cause unreasonable fear," he said. Though a pandemic sparked by a coronavirus has never been seen before, he added, the world has also "never before seen a pandemic that can be controlled," implying that this may be possible with COVID-19.

As I write this, much of the U.S. has been shut down with people asked to remain in their homes except for performing essential errands — a provision that no one can recall in recent memory. However, a look at pandemics throughout history verifies Adhanom's optimism, as never before did we have the communications systems and medical abilities available now.

Many Have Heard Scary Plague Stories

Many of you reading this may have grown up exchanging scary stories you had heard about the plague and the "Black Death," perhaps around a campfire. You may also know of Edgar Allan Poe's 1845 frightening short story, "The Masque of the Red Death,"2 in which nobles try to escape a plague by locking themselves in an abbey and holding a masquerade ball.

A ghoulish stranger finds his way into the abbey, according to the story, and even though the stranger proves to be an empty costume with no person inside, all the nobles die of the Red Death.

While the Red and Black Deaths scared schoolchildren for ages, scholars think the Red Death that Poe fabricated for his story was actually tuberculosis (TB), which his wife was suffering from at the time.3 The disease, also called consumption, took other close members of Poe's family including his mother, foster mother and brother.4 The empty visitor is now seen as a symbolic narrative device.

The sudden death that the plague and tuberculosis posed in Poe's day and their spread were indeed frightening and interpreted, like other pandemics, as divine punishment. But we now know that both diseases, as well as leprosy, which was also pandemic in the Middle Ages,5 are caused by bacteria and therefore treatable with antibiotics.

Plague,6 TB and leprosy, now called Hansen's disease,7 still exist today but no longer terrify people because we understand microbial pathogens and transmission. We know the plague is caused by the Yersinia pestis bacterium,8 TB by the Mycobacterium tuberculosis bacterium9 and Hansen's disease by Mycobacterium leprae.10

Certainly, the age of jet travel has heightened the spread of pandemic-capable diseases, and excessive antibiotic use has created resistant versions of many bacteria. But unlike in Poe's day and the epochs before him, our understanding of microbial pathogens and ways to address them has removed much of the fear of pandemics.

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There Were Several Plagues, Not Just One

"The plague" occurred centuries ago and decimated entire populations. The bubonic strain of the plague, the most common, was characterized by swollen lymph nodes called "buboes" and killed from 30% to 60% of its victims.11 However, not everyone realizes there were actually several plagues over the centuries.12

The Plague of Justinian started in Constantinople in 541 AD and rapidly spread across Europe, Asia, the Middle East and North Africa taking the lives of 30 million to 50 million people. At the time, that would have equaled half the world's population.13

In 1347, 800 years later, the plague reared its ugly head as the Black Death in Europe, claiming 200 million lives in four years, one-third of the world's population.14 The Black Death was so devastating that it changed politics forever: England and France declared a truce to their ongoing war and the British feudal system collapsed.

During the Black Death and subsequent pandemics there was no scientific understanding of disease transmission, but there was a growing awareness that proximity somehow heightened the problem — a first nod to the concept of social distancing.15

That is why it was decided in Venice during the Black Death that arriving sailors had to stay on their ships for 30 days until it was clear they were disease-free in an early demonstration of the concept of quarantine, called "quarantino" at the time.16 Still, outbreaks of the plague continued unabated despite early quarantine efforts, according to

"London never really caught a break after the Black Death. The plague resurfaced roughly every 20 years from 1348 to 1665—40 outbreaks in 300 years. And with each new plague epidemic, 20 percent of the men, women and children living in the British capital were killed.

By the early 1500s, England imposed the first laws to separate and isolate the sick. Homes stricken by plague were marked with a bale of hay strung to a pole outside. If you had infected family members, you had to carry a white pole when you went out in public."

Two hundred years after London's 1665 Great Plague, a third plague surfaced in 1855, which was concentrated in China and India, and killed an additional 15 million people.18

Finding the Cause of the Plague Reduced the Terror

Panic and suspicion of others is the hallmark of pandemics like the plague because transmissibility isn't known and people are terrified. In England, dogs and cats were suspected of spreading the disease and slaughtered by the hundreds of thousands,19 which only intensified the pandemic since rats, which no one knew were spreading the disease, had no predators.20

Finally, the cause of the plague was revealed. According to research published in Clinical Microbiology and Infection:21

"The causative bacterium of plague was described and cultured by Alexandre Yersin in Hong Kong in 1894, after which transmission of bacteria from rodents by flea bites was discovered by Jean-Paul Simond in 1898. Effective treatment with antiserum was initiated in 1896 … supplanted by sulphonamides in the 1930s and by streptomycin starting in 1947 …

Serological diagnosis with fraction 1 antigen to detect anti-plague antibodies was developed in the 1950s. Vaccine development started in 1897 with killed whole bacterial cells, and this was followed by a live attenuated bacterial vaccine, leading to millions of persons receiving injections."

The plague still exists today but no longer strikes panic in the public because its etiology from rat fleas is now known.22

The Smallpox Pandemic Was Also Terrifying

Just like the plague, many have heard frightening stories about historical smallpox pandemics. After a high fever and pain, smallpox causes cratered pockmarks all over the body, disfigurement and occasional blindness, and kills as many as 30% of its victims.23

As with the plague, millions died from smallpox over the centuries, and fear and mistrust were rampant until the virus that causes it, variola, was identified and treatments were developed. Historians now believe that what may have been termed the plague in early pandemics was actually smallpox. According to

"Many historians speculate that smallpox likewise brought about the devastating Plague of Athens in 430 B.C. and the Antonine Plague of A.D. 165 to 180, the later of which killed an estimated 3.5 million to 7 million people, including Emperor Marcus Aurelius, and hastened the decline of the Roman Empire …"

Smallpox was initially treated with "variolation," in which pus from stricken patients was introduced into healthy people, but the disease continued to spread. According to

"Variolation notwithstanding, smallpox continued wreaking havoc on princes and paupers alike. In the 17th and 18th centuries, it killed several reigning European monarchs, including Habsburg Emperor Joseph I, Queen Mary II of England, Czar Peter II of Russia and King Louis XV of France … in Europe alone, an estimated 400,000 commoners were succumbing to smallpox annually."

In 1796, Edward Jenner, an English doctor, developed a vaccine against smallpox. While it's often said that this is what defeated the disease, there is evidence that it wasn't vaccines but, rather, isolation and sanitation that overcame smallpox.

Influenza Pandemics Have Also Been Deadly

Compared with plague and smallpox, influenza or "flu" pandemics occurred much later in recorded history, but they have been just as devastating. According to Business Insider, in 1889:26

"The first significant flu pandemic started in Siberia and Kazakhstan, traveled to Moscow, and made its way into Finland and then Poland, where it moved into the rest of Europe. By the following year, it had crossed the ocean into North America and Africa. By the end of 1890, 360,000 had died."

Unlike plague, TB or Hansen's Disease, influenza is caused by a virus, arguably harder to treat than the bacteria that cause diseases. According to the News Observer:27

"A virus only works by invading a cell within an organism and taking over that cell's machinery to reproduce itself. By itself, it doesn't contain all ability to do everything it needs to survive and replicate. It essentially has to parasitize that other cell … for many viruses, in particular, we don't have very effective therapy."

The 1889 flu that originated in Russia was followed by the Asian flu of 1957-1958, which killed 1.1 million globally and 116,000 people in the U.S.28 Just 10 years later in 1968, the Hong Kong flu, an adaptation of the Asian flu, surfaced killing 1 million globally and about 100,000 in the U.S.29

The granddaddy of all flu epidemics and the one that is most on people's minds during the coronavirus pandemic is the Spanish flu epidemic of 1918. According to the U.S. Centers for Disease Control and Prevention:30

"The 1918 influenza pandemic was the most severe pandemic in recent history … Although there is not universal consensus regarding where the virus originated, it spread worldwide during 1918-1919. In the United States, it was first identified in military personnel in spring 1918.

It is estimated that about 500 million people or one-third of the world's population became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide with about 675,000 occurring in the United States …

… control efforts worldwide were limited to non-pharmaceutical interventions such as isolation, quarantine, good personal hygiene, use of disinfectants, and limitations of public gatherings, which were applied unevenly."

Disease Pandemics Have Continued

The 1968 Hong Kong flu was not the last influenza pandemic. Many will remember the 2009 H1N1 flu pandemic that surfaced a little over a decade ago. According to the CDC:31

"In the spring of 2009, a novel influenza A (H1N1) virus emerged. It was detected first in the United States and spread quickly … From April 12, 2009 to April 10, 2010, CDC estimated there were 60.8 million cases, 274,304 hospitalizations, and 12,469 deaths in the United States."

Another recent pandemic was the HIV/AIDS outbreak, which exploded in the 1980s. According to the CDC:32

"First identified in 1981, AIDS destroys a person's immune system, resulting in eventual death by diseases that the body would usually fight off …

AIDS … is believed to have developed from a chimpanzee virus from West Africa in the 1920s … Treatments have been developed to slow the progress of the disease, but 35 million people worldwide have died of AIDS."

Then in 2003, SARS (Severe Acute Respiratory Syndrome) erupted in China. According to the CDC, SARS:33

" … is believed to have possibly started with bats, spread to cats and then to humans in China, followed by 26 other countries, infecting 8,096 people, with 774 deaths. SARS is characterized by respiratory problems, dry cough, fever and head and body aches and is spread through respiratory droplets from coughs and sneezes.

Quarantine efforts proved effective and … the virus was contained and hasn't reappeared since. China was criticized for trying to suppress information about the virus at the beginning of the outbreak."

According to research from the National Institutes of Health, the current coronavirus is a form of SARS but with greater communicability:34

"The results provide key information about the stability of SARS-CoV-2, which causes COVID-19 disease, and suggests that people may acquire the virus through the air and after touching contaminated objects …

SARS-CoV-1 was eradicated by intensive contact tracing and case isolation measures and no cases have been detected since 2004 … In … [a] stability study the two viruses behaved similarly, which unfortunately fails to explain why COVID-19 has become a much larger outbreak."

From the original plague to the 1980s "plague" of AIDS, eventually the "codes" of the pathogens have been cracked and treatments and other measures, like increased sanitation and personal hygiene, found to end the pandemics — and history will likely continue to repeat itself.