• P.K. Peterson

Pandemics 101: Lessons Learned

“You may have to fight a battle more than once to win it.”

Margaret Thatcher

“Above all, don’t fear difficult moments. The best comes from them.”

Rita Levi-Montakini, Nobel Laureate

Every pandemic is unique. To quote Adam Kucharski, a professor at the London School of Hygiene and Tropical Medicine, “There’s a saying in my field: if you’ve seen one pandemic, you’ve seen one pandemic.” Despite the fact that every pandemic is unique, I believe there are lessons learned from other pandemics that are useful in responding to COVID 19. Before I discuss these lessons, the COVID-19 pandemic must be put into a historical perspective. (Note: the terms “epidemic”—an infectious disease that affects a large number of people across a wide area— and “pandemic” —a global epidemic—are often used interchangeably in the medical community, as they will be in this Germ Gem post.)

Pandemics are not new. Pandemics have been with us throughout human history. And germs have always been their root cause, but we didn’t understand this until the last half of the 19th century. Thus, it is difficult to identify which scourges in human history were caused by which microbes. Wikipedia provides a List of 245 epidemics dating as far back as an influenza epidemic in 1200 BCE, but the number of people who died in that epidemic is unknown. Twenty-one of the remaining epidemics on the list had an estimated death toll of more than 1 million. And then there were super-devastating epidemics, including: the Plague of Justinian (541-542) with 25-100 million deaths; the Black Death (1346-1353) with 75-200 million deaths; smallpox (1877-1977) with 500 million deaths; 1918-1919 influenza with 50-100 million deaths; and AIDS (1981-present) with 32 million deaths.

During the course of my four-decade career as an infectious diseases physician, there have been six epidemics or pandemics: HIV/AIDS; Ebola virus disease; 2009 H1N1 influenza (a.k.a. the swine flu); Zika; and the three 21st century pandemics caused by marauder coronaviruses, namely, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and COVID-19. All of these pandemics sparked panic. Despite the long history of pandemics throughout the centuries and our more recent history over the past four decades, until COVID-19 hit, many people currently living in the developed world had become complacent to the disastrous impacts of pandemics. Perhaps because the mortality was highest among the poor and disenfranchised, these diseases didn’t seem to have a long-term effect on most people in the general public in the United States. This may explain why COVID-19 is such a wake-up call for many of us, reminding us that infectious diseases are an ongoing threat to us all.

Countless articles and books have been written about each of these recent epidemics, so it is difficult to do justice to any one of them in a single Germ Gem post. Thus, I’ve highlighted only a few that I believe are the most instructive as they relate to the ongoing battle against COVID-19.

Smallpox. Caused by variola virus, smallpox (popularly referred to as “the speckled monster” because of its classic skin lesions) killed between 20-60% of those infected. It is most notable for two reasons: (1) it killed more people than all wars in history combined, and (2) it’s the only human pathogen that’s been eradicated from the face of the Earth—the last case of natural smallpox occurred in Somalia in 1978.

Lesson 1: Never give up. The heroic victory over smallpox is credited to vaccination, the origin of which can be traced to the English physician and father of vaccinology, Edward Jenner, in 1798. It took almost 200 years to eradicate small pox. And, we are still battling all other pathogens that caused epidemics.

Lesson 2: Collaborate. The victory over smallpox virus underscores why developing a vaccine is such a high priority in the battle against COVID-19. It also demonstrates how an international program led by the World Health Organization, in collaboration with non-profit organizations and several brilliant public health leaders, can surmount such a challenge.

Lesson 3: Be patient. The Roman Emperor and famous stoic philosopher, Marcus Aurelius Antonius, faced one of the worst pandemics in European history during the last 14 years of his life. The Antonine Plague, named after him, was probably caused by smallpox virus. It killed an estimated 5 million people, possibly including Marcus himself. And it likely reinforced the stoic virtues of patience, wisdom, and self-discipline, all of which are valuable in dealing with COVID-19.

The Plague. Plague is a bacterial infection, not a viral one. There are actually three different kinds of plague. One form, pneumonic plague, is a highly lethal infection of the lungs that can be spread by coughing. Another form, septicemic plague, occurs when the plague bacterium invades the bloodstream, and is an almost certain death sentence. People dying of septicemic plague turn a very dark color-hence the name Black Death. The third and most common form is the bubonic plague, referring to enlarged lymph nodes or “buboes” in the groin, rivals the devastation caused by small pox and is fatal in 50% to 60% of cases.

There have been 28 epidemics of bubonic plague in recorded history, including: the Great Plague of Athens (429-426 BCE) that killed 75,000-100,000; the Plague of Justinian (541-542) that brought down 25-50 million people in the Eastern Roman Empire; the Black Death (1346-53) that wiped out 30 to 60% of all humans in Europe; and the Great Plague of London (1665), that killed 100,000 Londoners—20% percent of the city’s population—in seven months.

Lesson 4: Help others. Rather than responding to the epidemic by fleeing to the countryside to avoid the plague, a small handful of people remained in London. Samuel Pepys, the essayist and diarist, was one of them. He stayed in town to help the sick and dying and chronicled the terrifying calamity in The Diary of Samuel Pepys. In a recent article in the Intelligencer, The Very First Pandemic Blogger,” Andrew Sullivan proposes that Pepys is the role model we all need for life in a plague (or pandemic as in COVID-19).

Lesson 5: Recognize the critical role of public health. During The Great Plague of London, governments in Europe, for the first time, got seriously involved in medical matters. Public health boards were created. These organizations built “pest houses” for the sick and set and enforced strict quarantine measures. Demonstrating that pandemics can foster unintended positive consequences, The Great Plague of London fostered the development of social distancing (Isaac Newton, a student at Cambridge at the time, was sent home, where he developed calculus).

Lesson 6: Hang in there even when things look like they’re getting worse. By late 1666, the plague had begun its retreat, only to be followed by the Great Fire of London that destroyed the city’s downtown. And to make matters even worse, there was the outbreak of the Second Anglo-Dutch War. Despite the plague, fire, and war, London survived, and in 1667 Pepys was busy putting his rooms back in order.

Influenza. There have been at least six pandemics of influenza. The latest was the 2009 H1N1 swine flu pandemic that killed an estimated 12,469 people. Based on many similarities between influenza and COVID-19—both are viral infections that are spread by respiratory droplets generated by coughing and sneezing and both cause major havoc in the lungs—many scholars have looked to influenza for guiding principles for understanding COVID-19.

The 1918-19 Spanish flu (the so-called “Mother of all Pandemics”) was the deadliest in history, infecting an estimated 500 million people worldwide—about one-third of the planet’s population—and killing an estimated 50 million victims, including some 675,000 Americans. The impact on the population was so severe that in 1918, American life expectancy was reduced by 12 years. A peculiarity of this flu pandemic was its predilection for young healthy individuals, many of whom were enlisting or fighting in World War I. (The casualties of troops in the “Great War” due to combat were by far outnumbered by those due to influenza.)

Lesson 7: Expect the unexpected. With the exception of the 2009 swine flu pandemic, the other modern flu pandemics occurred in the 20th century and had their origin in birds (Spanish flu 1918-19, Asian flu 1957, and Hong Kong flu 1968). One feature that all four modern flu pandemics shared with each other and with COVID-19 is they were all unpredicted. And what many epidemiologists feared the most (and were predicting) was that another catastrophic flu pandemic was just waiting in the wings that would rival the 1918-19 pandemic. What we got instead is COVID-19.

Seasonal influenza, which comes along every year with a mutated viral strain requiring an annual modification of the flu vaccine, is also serious. It kills on average about 50,000 Americans a year. Like COVID-19, the biggest risk groups of mortality of seasonal flu are the elderly and those with underlying medical conditions. But comparing COVID-19 and seasonal flu death tolls is considered by some experts to be misleading because COVID-19 is far more dangerous and wreaking far more havoc than seasonal flu ever has.

Lesson 8: Don’t take your eye off the ball. Whether the comparison of COVID-19 with pandemic influenza is equally misleading remains to be seen. In analyses of the impact of the 1918-19 flu on the memories of those who lived through it, scholars have found a surprising loss of cultural memory. Almost everyone must have lost loved ones or neighbors, and yet the memories were rarely talked about. Perhaps it was because the calamities of World War I and the Great Depression were much more vivid.

Let’s not fool ourselves, the threat of pandemic influenza hasn’t disappeared just because COVID-19 came along. Until COVID-19 struck in December 2019, development of a “universal influenza vaccine”—a vaccine that would prevent infections by all influenza strains—was seen by many experts as a top priority. And in my view it still is.

HIV/AIDS. With the exception of HIV, none of the microbes that cause sexually transmitted diseases (STDs) appear in Wikipedia’s list of 245 epidemics. The microbes that cause plague, smallpox, influenza, and measles—carried by European explorers to the New World—were the primary reason behind the Europeans’ swift military victories over Native Americans. In addition, it seems likely that Christopher Columbus or someone in his crew also spread the pathogen (Treponema pallidum) that causes syphilis—along with news of the Americas—to Europe when he returned.

It’s likely that many of the microbes that cause STDs have smoldered out of sight in pandemic proportions for as long as humans have enjoyed sex. But the taboo on discussing sexual behavior was lifted when HIV/AIDS emerged in the United States in 1981. Since then, HIV/AIDS rapidly spread throughout the world. By 2018, 75 million people had been infected with HIV and about 32 million people had died of the infection (AIDS). Globally, an estimated 37.9 million people were living with HIV in 2018. (Contributing to these numbers are cases acquired by another mode of viral transmission, injection drug use, accounting for about 5-10% of cases.)

Lesson 9. Stay safe and stay hopeful. Despite the formidable challenges posed by HIV/AIDS, a UNAIDS report was issued in 2014 suggesting that its “Fast-Track” strategy could end the AIDS epidemic as a global health threat by 2030. But without a vaccine, how is that even conceivable?

First, safe sex (mainly using condoms) and safe needle sharing programs make a big difference. In the case of COVID-19 staying safe means covering coughs and sneezes, rigorous handwashing, social distancing, and wearing a mask, especially when you have symptoms.

Second, and most important, are achievements by untold numbers of researchers in governmental organizations, academia, and the pharmaceutical industry who discovered drugs that can suppress the replication of HIV (i.e., to levels so low that the immune system recovers), and can prevent infection (i.e., in the case of those who are uninfected when the drugs are taken before having sex).

Within the context of COVID-19, progress at this time—less than six months into the pandemic —toward finding effective medications and a vaccine is remarkable. And I believe, having witnessed the accomplishments in the field of HIV/AIDS, the goal of controlling, if not defeating COVID-19, is certainly achievable.

The coronavirus era. While public health experts were worrying about the emergence of the next flu pandemic and cadres of researchers and healthcare professional were battling HIV/AIDS, as well as a number of other formidable enemies (including tuberculosis, malaria, cholera, dengue, and yellow fever to name just a few), along came the surprising coronavirus infections: SARS, 2002-2003; MERS (2012-present), and COVID-19 (2019-present).

Lesson 10. Be prepared. While all three of these coronavirus diseases share some features, including that they’re all zoonotic infections (transmitted from animals to humans) and are primarily respiratory tract infections, they have striking differences in transmissibility, mortality, pathogenesis, and clinical features (the exact nature of which are still being described).

As we watch the tally of cases of COVID-19 (5,407,604) and deaths (345,057), globally as of May 24th, continue to mount and we try to figure out why some countries or states have lower numbers than others, one thing seems clear to me—those that were prepared have done better. And this so far is the overriding lesson of COVID-19 for governments and policy makers—be prepared for the next pandemic.

I am writing this Germ Gem on Memorial Day. So as I remember and am so thankful for all those who gave their lives to protect democracy, I can’t help but think of all the doctors, nurses, and first responders who have sacrificed their lives in the battle against COVID-19. And I’m also deeply moved by the increased acts of kindness and togetherness (even in the face of sheltering in place) that I witness every day. I believe that just like the awful wars of the 20th century, we will win the battle against COVID-19.

Su Hu Image 3_edited.jpg

Main Page images courtesy of Shuxian Hu, MD. Dr. Hu is a scientist in the Neuroimmunology Research Laboratory at the University of Minnesota.


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© 2020 by Phillip K. Peterson
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