In the years after the Spanish Flu struck, children skipped rope to this rhyme:

I had a little bird
Its name was Enza
I opened the window
And in-flu-enza

The Worst Flu Pandemic on Record

The most popular reference in the contemporary discourse on influenza pandemics is the Spanish Flu of 1918-19. The truly devastating nature of this pandemic and the overwhelming failure of officials to respond effectively are often cited, though in support of a variety of differing arguments. So, what actually happened in 1918-19? This section provides an overview of what we know today about the events 90 years ago.
On this page…
  A disease that struck with frightening speed »
  Why Spanish Flu? »
  WWI and the pandemic: “A pattern of complete insanity” »
  Why scientists call it “The mother of all pandemics” »
  Three main waves in two years »

A disease that struck with frightening speed

In 1918-19, the world saw the most catastrophic pandemic in modern history. More people died from the H1N1 strain that circulated at the time—Spanish Flu as it became known—than from fighting in World War I.

In the annals of modern medicine, the Spanish Flu of 1918-1919 is the standard of virulence against which all other infectious diseases are measured. Historians have long agreed that at least 20 to 40 million people died in a pandemic that reached from the ice floes of Alaska to the jungle villages of Gambia. But because of spotty record-keeping and no definitive diagnostic test at that time, this estimate may be too low. Epidemiologists today look back at a far larger toll—at least fifty million deaths and perhaps up to 100 million.

The influenza struck with frightening speed. Some people woke up in the morning feeling well, became sick in the early afternoon, and died at night. Those who fought off the disease’s initial attack frequently faced a secondary onslaught of bacterial pneumonia lasting a few days. For many it was a matter of dying sooner or later.1

One-fifth of the world’s population (about two billion at the time) came down with the disease.2 In the United States, the infection rate was higher—28 percent—resulting in 675,000 deaths, which depressed the average life expectancy by 10 years.
The toll of death worldwide surpassed combat fatalities from all wars of the 20th century.

Why Spanish Flu?

The outbreak became known as the Spanish Flu because the virus killed a staggering eight million people in Spain in a single month—May 1918. Spain wasn’t necessarily hit harder than other countries. But as John Barry explains in his book3, Spain was a non-combatant in World War I and thus its press was freer to report the numbers of sick and dead.

The origin of the virus was not Spain, though public health officials then and now cannot pinpoint where it began. One theory traces its beginnings to an army training facility, Camp Funston (now Camp Riley) in Kansas, where hundreds of young men suddenly fell ill with what was then called the “three-day fever.”4

WWI and the pandemic: “A pattern of complete insanity”

In the midst of wartime, governments and medical authorities failed to recognize the epidemic in the making. The Spanish Flu hitched a ride around the globe in the ships conveying troops to and from the battlefields of World War I and found fertile ground in the crowded trenches of Europe.

According to historian Alfred Crosby, the interweaving of the war and the pandemic made for what seems now “a pattern of complete insanity.”5

Wherever masses gathered—and they did regularly at war bond rallies and enlistment centers, for instance—people coughed and sneezed on each other. Armistice Day November 11, 1919 drew millions around the world into each other’s arms to celebrate, and into the embrace of influenza.

Meet the mother of all pandemics

The world had known influenza before, but never of this ferocity. The Spanish Flu claimed its victims at a rate of 2.5 percent, compared to a typical epidemic death rate of 0.1 percent.6

It struck disproportionately hard at young adults from age 20 to 40, who made up about half of all deaths.7

The Spanish Flu attacked sparsely populated villages and crowded cities with equal intensity:8

In Russia and Iran, 7 percent dead.
In parts of Senegal, Sierra Leone, Spain and Switzerland, 10 percent.
In Nome, Alaska, 176 Eskimos died in a village of 300.
In Japan, one-third of the population came down with the disease.
In Cape Town, South Africa, 4 percent of the population succumbed within four weeks of the outbreak.

Three main waves in two years

Asia was particularly hard hit. As John Barry, author of “The Great Influenza,” writes, “Throughout the Indian subcontinent, there was only death. Trains left one station with the living. They arrived with the dead and dying, the corpses removed as the trains pulled into the station.”

The suffering of the sick was horrendous. About 10 to 20 percent of the infected experienced acute pain even when they moved their eyes. Their weakened lungs couldn’t supply enough oxygen so their skin turned blue. Fits of coughing ruptured abdominal muscles. Blood spurted from every opening. In the worst cases, fluid filled their lungs, literally drowning the helpless victims.9

The Spanish Flu swept across the earth in three main waves over two years. Eventually, however, it stopped killing quite so many people. Everyone who was genetically most vulnerable died. Survivors developed some immunity and the virus itself may have mutated into a less virulent form. Indeed, researchers now believe that today’s H1N1 subtype is a much milder descendent of the long ago strain that caused Spanish flu.
“Don’t Get Scared!”

Excerpt from “The Great Influenza: The Story of the Deadliest Pandemic in History,” by John Barry, Penguin Books, 2004.

So people watched the virus approach, and feared, feeling as important as it moved toward them as if it were an inexorable oncoming cloud of poison gas. It was a thousand miles away, five hundred miles away, fifty miles away, twenty miles away…

Wherever one was in the country, it crept closer—it was in the next town, the next neighborhood, the next block, the next room. In Tucson the Arizona Daily Star warned readers not to catch “Spanish hysteria!” “Don’t worry!” was the official and final piece of advice on how to avoid the disease from the Arizona Board of Health.

“Don’t get scared!” said the newspapers everywhere. Don’t get scared! they said in Denver, in Seattle, in Detroit; in Burlington, Vermont, and Burlington, Iowa, and Burlington, North Carolina; in Greenville, Rhode Island and Greenville, Mississippi. And every time the newspapers said, Don’t get scared! they frightened.


  1. D.M. Morens, J.K. Taubenberger, A.S. Fauci, “Predominant role of bacterial pneumonia as a cause of death in pandemic influenza: implications for pandemic influenza preparedness”, The Journal of Infectious Diseases 198, (Oct. 1, 2008): 962-970.

  2. Molly Billings, The Influenza Pandemic of 1918, modified February 2005.

  3. John Barry, The Great Influenza: The Story of the Deadliest Pandemic in History, Penguin Books, 2004, p. 4.

  4. Gina Kolata, Flu: The Story of the Great Influenza Pandemic of 1918 and the Search for the Virus that Caused It, Farrar, Straus & Giroux, 1999, p 10.

  5. Alfred W. Crosby, America's Forgotten Pandemic: The Influenza of 1918, Cambridge University Press, 2003.

  6. Jeffery K. Taubenberger, David M. Morens, 1918 Influenza: The Mother of All Pandemics, January 2006.

  7. Barry, op. cit., p. 4.

  8. Barry, op. cit., p. 362, 363.

  9. Commonwealth Scientific and Industrial Research Organisation, CSIRO explores protecting poultry from avian influenza, June 2007

1 Comment on The Worst Flu Pandemic on Record
Saurav Kunwar says:
April 14, 2010 at 4:56am
This article was a great help. Many thanks to you all
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