Each year we are flooded with large ad campaigns encouraging us to get our flu shots. Most of us probably wonder why. The flu doesn’t seem that bad, right? But then, every few years, a deadly bout of swine flu, or bird flu spreads through society and we understand a bit better. But in 1918 the flu demonstrated just how bad it could be. We had an outbreak of the disease like no other. The Spanish flu would go on to kill more people than the the first world war, in just a matter of months. This is the story of the pandemic that touched every corner of the globe. In a British army hospital and staging camp in Étaples France, the Spanish flu jumped from a bird, to a pig, and then to a soldier. This nameless soldier did not know it, but his body incubated a disease that set off the deadliest outbreak in history. The flu was spread by the close quarters and massive troop movements of the First World War. With so many millions of troops moving and living together and 20th century transportation making contact with new people commonplace, the virus proliferated at a rate never seen before. Every human the virus infected would be a Petri dish. The virus could mutate, evolve, and eventually become more lethal to Humans. In a matter of weeks, the virus was all over the world. The disease became known as the Spanish Flu as news of it spread through the allied forces. Spain was not participating in the war, and so they did not employ a wartime censorship on the press. Because of that, the first stories to come out about the flu came from Spanish sources. And so the virus that jumped to humans in a British hospital in France, got the name the Spanish flu. The Spanish flu had an amazing ability to spread, but that’s not the only noteworthy thing about it. It was also the deadliest flu ever encountered. It killed about 10 to 20% of those who contracted the disease, totaling about 3 to 6% of the earth’s population. To understand what made the flu so deadly, I have contacted Chad from Childish Wonder to explain the science. The great influenza pandemic of 1918 was the most destructive pandemic in recorded history, killing more people than all the casualties from World War One. It is estimated to have infected over a quarter (28%) of the world’s population and resulted in the death of 50 –100 million people. In fact, there were so many deaths that the American life expectancy dropped by 10 years during this time. The weird thing about this pandemic is that unlike yearly influenza epidemics, which usually have the greatest impact on infants and the elderly, the 1918 influenza pandemic took its greatest toll on healthy adults between the ages of 20 and 40. But why would that be? Well, the virus in 1918 was so efficient at invading the lungs that the immune system was forced to mount a massive response to it. And what ended up killing these people wasn’t actually the virus itself, it was these people’s own immune systems. Typically, the body can fight off the influenza virus before it can really penetrate, but once the 1918 virus got into the lungs, the immune system had to do everything it possibly could to get rid of it. And it didn’t hold back. Part of its defense was to produce a HUGE amount of cytokines, proteins that increase blood flow and recruit more immune cells to the site of infection. The immune cells and cytokines in the lungs then waged war. Unfortunately, the casualties of this war ended up being their own bodies. This attack, sometimes called a cytokine storm, damaged uninfected tissue as well, and caused fluid to leak from the blood vessels, filling up their lungs. And it didn’t stop there, cytokines leaked into the rest of the circulation as well, causing high fevers, uncontrollable bleeding, and eventually, multiple organ failure and death. So it wasn’t actually the virus that killed, it was the immune response. And having a healthy immune system was a liability rather than an asset. Those with weaker immune systems, were actually the ones able to survive as their bodies couldn’t generate such massive and devastating responses. But healthy young adults could, and sadly, they were the ones that disproportionately made up the victims of this pandemic. Thanks Chad. By August of 1918, the flu had undergone a new, much deadlier mutation; Quickly spreading to France, Sierra Leone, and the United States. The ongoing war actually helped make it deadlier. Under normal conditions, viruses that cause mild illness actually spread the easiest. However, on the front lines of a battlefield, a mild flu does not release a soldier from duty. Only deadly, serious diseases send soldiers back to the giant hospitals filled with immune compromised soldiers. Through this, the deadliest strains were the one’s that survived and spread. Even in places with relatively low death rates, the Spanish flu ravaged communities. It instilled in people a fear of one another, and halted the delivery of public services. Infected by ships coming from New Zealand, the pacific islands of Fiji, Nauru, and Tonga were hit extra hard. They lost as much as 15% of their population. The flu spread to all corners of the earth. The only place that didn’t experience a severe outbreak of it, was a tiny island off the coast of Brazil. And possibly Antarctica, unless there was a penguin flu we don’t know about. Then out of nowhere, the Spanish flu disappeared. Just as fast as it began. There was no vaccine, no cure, it just simply mutated into a milder form. It did however leave a deep legacy. Historian Andrew Price-Smith argued that the heavier death tolls from the Spanish Flu in Germany and Austria are what tipped the stalemated First World War in favor of the allies. It also might have given the predominantly female nursing corps a shot in the arm, showing that they could help when the mainly male doctors without a vaccine or cure couldn’t. This might have emboldened the profession and pushed more women to go to higher education for nursing. The flashier First World War going on at the time, meant that within a decade or two, the Spanish flu was largely forgotten. It was not until the bird flu scares of the 90s and 2000s that this forgotten pandemic was remembered. We tend to think great events in history happen because of human agency. The allied victory in the First World War was due to a surge of american troops, diseases are cured by doctors, and the industrial revolution was a result of strong government policy. But we didn’t control the Spanish flu. It came and went all on its own. Maybe sometimes we don’t have as much power as we think. Maybe sometimes things just happen. In many ways we’re simply animals, and our ideas of control over our own destiny are often greatly exaggerated. How much control do you think we actually have over our own history? Let me know what you think down below. If you want more history that goes off the battlefield subscribe for more Step Back.