According to Nassim Nicholas Taleb, a “Black Swan” event has three qualities:
- It is an outlier and nothing in the past suggests its possibility.
- It has an extreme impact.
- Finally, despite being an outlier, retrospective explanations make the event seem explainable and predictable.
It seems that many people think that the global Covid-19 pandemic is a Black Swan event. It’s not.
In fact, pandemics have been a part of human history from the beginning. The number of recorded epidemics is enormous. Epidemics that affect many people are less common, but are by no means rare.
The following image shows a timeline of major epidemics since 1850, where major epidemics are defined as killing half a million people or more. There are 16.
The length of the bar indicates how long each epidemic lasted. The height of the beam is a minimum estimate of the number of deaths.
What is immediately clear is that there is nothing special about Covid-19. Several epidemics have done more damage. For example, the “Third Plague,” a resurgence of the bubonic plague that caused the Black Death in the mid-1300s, killed at least 12 million people at a time when the world’s population was only one-sixth its current size. The global flu pandemic of 1918 may have killed up to 100 million people in about the same time as Covid-19 killed anywhere from 5 million to 19 million out of a total population four times the size it was a century ago.
In fact, of the two ongoing pandemics – Covid-19 and HIV/AIDS – Covid-19 was the least significant in terms of absolute fatalities. At its peak in 2004, 1.7 million people died each year from HIV/AIDS. Even though Covid-19 has killed more than HIV/AIDS in one year, with vaccines and natural immunity, the death toll from Covid-19 is unlikely to reach that of HIV/AIDS.
In addition, there is little evidence that epidemics are slowing down. Despite huge breakthroughs in science and medicine in the twentieth century, there were still eight pandemics (epidemics with a global reach) that killed 500,000 people each. Since the flu pandemic of 1957, Covid-19 has created an average of one pandemic per decade, a trend that is likely to continue into the 21st century.
One reason for this is that perhaps the most important medical breakthrough in the fight against infectious diseases is the development of antibiotics. Arsphenamine, widely regarded as the first synthetic antibiotic, was discovered in 1907 and used in its treatment by a German physician, Paul Erlich. Those early arsenic-derived compounds were followed by penicillin in 1930 and sulfonamide antibiotics from 1933. Antibiotics are estimated to have saved many millions of lives in the twentieth century. But antibiotics are only effective against bacterial pathogens. Most major pandemics since 1800 have been caused by viruses.
Our greatest weapons against viruses are vaccines and antivirals. But unlike antibiotics, each of which can target a wide range of bacterial pathogens, the relationship between vaccines and viruses is very specific: each virus requires a different vaccine. In fact, for viruses that evolve quickly, such as the flu, we need different vaccines for different virus strains. And vaccines take some time to develop. Despite the unprecedented speed at which Covid-19 vaccines have been developed, a majority of the world still lacks access to these vaccines nearly two years after the start of the pandemic. A vaccine for HIV/AIDS has yet to be approved after 30 years of trying.
All this means that our primary medical breakthroughs are of limited use against emerging viral diseases, most modern pandemics. So if the future is anything like the past, we can expect a new pandemic disease about once every decade. The next one could appear in less than a decade, or it could become a reality in two decades. But it will come.