The 1918 Pandemic: Lessons Not Learned?

I read a terrific book recently titled The Great Influenza: The Story of the Deadliest Pandemic in History by John Barry. It was originally published in 2005; however, I suspect it is still at the top of most medical reading lists.

The 1918 flu pandemic

The book described 1918 as a world remarkably like the one we are about to leave behind. In 1918, information about the pandemic was challenging to obtain; businesses, churches, and even small public gatherings were forbidden.

How do the death tolls compare?

In the period 1918 to 1920, approximately 675,000 Americans died because of the pandemic.¹ Percentage-wise, the 675,000 total is much worse than what we see today. In 1918, it was estimated that the U.S. had a total population of around 103 million.¹ So, the H1N1 1918 pandemic killed between 0.50 and 0.86 percent of the U.S. population. 

The U.S. estimated population in 2021 is 337 million. So, if the same percentage of the U.S. population died due to COVID-19, the death toll would be around 1.6 million instead of an estimated 545,000 as of March 25, 2021.^2,3

Interesting learnings about the 1918 flu

What attracted my attention were five things about the 1918 pandemic.

1. The place of origin. We have heard much negativity about China being the source of the COVID-19 pandemic. In 1918, it is believed that the first reports of the virus occurred in Haskell County, Kansas.¹ Talk about the shoe being on the other foot. We should remember that the Spanish Flu killed far more worldwide than COVID-19 so far and that the policies of the United States, specifically related to World War One, helped spread the virus around the globe.¹

2. The scientists raced at first to identify the cause of the sickness. Until the scientists figured out the cause of the illness was, they could not battle it. In 1918, significant effort went into debating and identifying the type of virus. Many scientists believed it was an identified flu virus. Still, others were determined that the pneumonia virus drove the pandemic. Flu won out.¹

3. The virus became more virulent and lessened over time. There was a curious progression. At first, with each interaction, the virus seemed to grow more virulent and then it started to collapse. These were termed "waves" that rounded the earth with the first iteration as relatively mild; people got ill and got over it - not a big deal. Then as the virus mutated, it picked up devastating speed and lethality. 

Then in the third wave, the virus stopped impacting so many and the death rate held steady. Then by the fourth iteration, the death rate and severity went down. This makes sense since, on each iteration, there were far fewer people to catch it (herd immunity), and those who were the most susceptible had died before the third wave.¹

4. The initial waves impacted the young the most. Those in their 20’s and 30’s had more reported cases and were more likely to die than other age brackets. There were a lot of theories about why this happened. One was that this age group practiced social-distance less (that is a modern term), and as such, they were the most exposed.¹

Another reason for this fact could have been that there were far fewer elderly people by a percentage of the population. Simply put, fewer people made it to being elderly. Diseases like cancer, heart disease, and accidents took a significant bite of the population apple year after year. If there are fewer elderly as a percentage of the population, it might be said that it is natural that less would die.¹

5. The flu was spread in large part because of World War One, but likely not in the way you might think. The prevailing theory (there are many) is that soldiers who were extremely ill either in Europe or in their home countries were assigned to care.  Many were transported back from France and Germany to their home countries. This assignment was to watch or, conversely, the transport home that exposed so many to the virulent virus, thus creating the second wave of the pandemic.¹

Theories about how the flu pandemic ended

Today, virologists tend to think that the pandemic stopped in part because of what mathematicians call ‘reversion to the mean’ which roughly means that “an extreme event is likely to be followed by a less extreme event” or, as the virus mutated after the second wave, it became more regular.⁴ As Barry points out, the virus was, after all, "just the flu." Yes, it mutated to be highly deadly, but then the genetic mean caught up to it and the virus started to act more like regular flu.

Finally, there is one other theory about the 1918 flu virus that, for some reason, fascinates me to no end. The makeup of the virus was not known until 1999.⁵ The hunt for the virus was like a detective novel and it involved exhuming corpses (the principal find came from a native woman in Alaska) and, in the end, reconstructing an active 1918 virus. This was a highly regulated process with the CDC allowing only one person in the room.⁵ If you wish to read about this remarkable story, check out The Deadliest Flu: The Complete Story of the Discovery and Reconstruction of the 1918 Pandemic Virus. It is worth the read.

And this relates to RA how?

How does this relate to rheumatoid arthritis? It turns out those pesky T cells that we use modern medications to suppress are the same ones that created the massive and deadly immune response in sufferers from the 1918 flu virus. 

Since the immune response was overwhelming in people who were sufferers in 1918, the discovery of the virus has given researchers a new avenue to study anti-TNF agents in mice. It has also opened the possibility of modifying current medications for future infections like the 1918 flu. Wow, that is some cool stuff! and you thought the 1918 pandemic was just history.