The Spanish flu–which infected one-third of the world’s population a century ago–is largely forgotten today. Will the same thing happen to our memory of the COVID-19 pandemic?

By Chris Wolski

Are we doomed to forget the COVID-19 pandemic?

The cynic in me says “yes.” And history backs me up. A century ago, the world was gripped by a flu pandemic that ultimately killed 50 million people and infected about 500 million, or one third of the world’s population1. What’s not as well known is that there was another pandemic that happened at the same time, that infected at least 1 million people worldwide and caused about 500,000 deaths2. The symptoms of the disease, Encephalitis lethargica, reads like a horror story, which completely mystified medical science for the better part of a decade (long after the Spanish Flu gave way to the Roaring ‘20s) until it simply disappeared. (I highly recommend the very excellent book, Asleep by Molly Caldwell Crosby, about the history of this epidemic).

There are two reasons why this and, to a large extent, the so-called Spanish flu have been forgotten. The first is that both diseases burned themselves out and disappeared. We, of course, still struggle with the flu every year—but nothing so virulent as the version faced in 1918-1919. There have been only about 80 reported cases of Encephalitis lethargica since it went silent in the late 1920s. The second is human nature; we want to put the unpleasant and the unspeakable behind us. Even with calls of “never forget” or “never again” in the wake of every tragedy over the past century—we do and it does.

The COVID-19 pandemic was certainly a wake-up call and occurred in much different circumstances than these previous pandemics. First, we understand disease much better than a century ago—the Spanish Flu was thought to be caused by bacteria—so we have treatments, and more importantly tests that can accurately diagnose the disease. Perhaps, just perhaps, this will allow us to remember.

However, as CLP Associate Editor Andy Lundin outlines in this month’s cover story, forgetting may be one of the biggest culprits in the recent outbreaks of Polio and other disease scourges that, until recently, had lived almost exclusively in history books or nineteenth-century novels.

What happens if we forget the COVID-19 pandemic? History will repeat itself.

The optimist in me sees that the past doesn’t have to be prologue this time. Diagnostic testing gives the unique opportunity to remain ever vigilant. So, for once, the pledges of “never forget” and “never again” can be fulfilled.

Featured Image: 1918-1919. An epidemic of Spanish Flu spread around the world. At least 20 million died, although some estimates put the final toll at 50 million. It is estimated that between 20% and 40% of the entire world`s population became sick. Photo: Dreamstime/Stock Image

Chris Wolski is chief editor of CLP.


  1. “1918 Pandemic (H1N1 virus).” Centers for Disease Control and Prevention. March 20, 2019.
  2. Leslie A Hoffman, Joel A Vilensky, Encephalitis lethargica: 100 years after the epidemic, Brain, Volume 140, Issue 8, August 2017, Pages 2246–2251,