The Spanish Flu pandemic of one hundred years ago bears striking similarities with the Covid-19 pandemic of today, but it also holds many differences. 

Numbers are always difficult to pin down, but researchers estimated that the so-called Spanish Flu killed 25 million people in the first six months alone. It led some people to predict the end of humanity at the time. 
Recent studies have suggested that, although the virus was indeed more lethal than other strains of influenza, the epidemic wasn’t fundamentally different from any other previous ones. 

Medical knowledge was a lot scarcer than today. At the time, scientist thought influenza was caused by a bacterium they called Bacillus Influenzae (today, we call it Hemoplilus Influrnezae). 
During the Russian Flu epidemic of 1889, Richard Pfeiffer, a student of Koch, claimed to have identified the bacterium that caused it. At the beginning of the 1900s, most doctors still thought that bacteria, not viruses caused the flu. This coloured the way they understood the flu and the pandemic and the way to fight it. 
In 1918, pathologists who cultivated bacterial colonies from the lungs of Spanish Flu victims did find Pfeiffer’s bacillus in some, but not in all. This puzzled them. The fact that vaccines against Pfeiffer’s bacillus benefited some patients and not others was also puzzling. Today we know that the vaccine was effective against secondary bacterial infection that caused pneumonia, the ultimate cause of death in most cases. But scientist didn’t know this at the time. 
Bacilli were visible under a microscope. Scientists slowly realised something else must be at play. Some other agents which they could filter out of a mixture but could not see under the microscope. They called these agents viruses. Because they were virtually invisible, scientists could not study them. There was indeed a debate about whether these were chemicals or small organisms. Yet, vaccines had been developed against viruses as far back as the 18th century, when the vaccine of smallpox was first developed. 

But there was no vaccine for the Spanish Influenza and in 1918. Antibiotics had not been developed yet. 
The fight against the Spanish Flu was harsh and deadly. And almost blind. 

Portray of the Spanish Flu

The Spanish Flu first appeared in spring 1918, and the first wave was generally relatively mild. The symptoms were typically the same of any other flu: chills, fever and fatigue. The sick usually recovered after several days. Reported deaths were generally low. 

Speculation had abounded about why the Spanish Flu spread so fast and large, and it is a fact that the Great War factored into it. The flu probably first took hold in the trenches of WWI, where it was easy for it to attack the malnourished, fatigued, often weakened body of the soldiers. 
Trenches and army barracks were crowded places, unusually unhealthy. All kinds of diseases had been spreading during the war years. Epidemics of influenza occurred in the trenches before. But one factor was different for the Spanish Flu: it hit at the end of the war. 
When demobilisation started, soldiers went home, dispersing throughout the world. There were all sorts of celebrations, gatherings and parties when the soldiers went home. Gatherings and crowds – even very large – commonly happened. Soldiers who had developed some resistance against the different flu strains in the trenches got in contact with people who had no defences against it. 
It was an easy circumstance for the virus to spread unchallenged. 

The second wave of the flu was a cataclysm.  
The flu attacked the respiratory tree, causing death by pneumonia and respiratory failure. It developed rapidly after the first onset of symptoms, and often, death occurred within five days (but sometimes it only took hours) due to massive pulmonary haemorrhage or pulmonary oedema. The patients’ skin turned blue, and fluids would develop inside the lungs, causing the sick to suffocate. 

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In October 1918, the second wave of the flu spread throughout the world, crowding hospital where doctors were at a loss as to how to cure it. Many of the doctors and nurses fell ill themselves, which added to a shortage of hospital staff caused by the war that was still going. Very often, young medical students had to face the emergency with very little knowledge of the illness and not much experience of anything else. 
It was a real fight, where doctors tried common sense but also other, less orthodox – and maybe less effective – cures. Because they had little actual knowledge of how influenza worked, there was no official cure. Quarantine, the century-old weapon against epidemics, was mainly employed. Hospitals created isolation wards. Governments implemented quarantine zones and prohibited gatherings. But there was little that would cure the sick. 
Only towards the end of the pandemic it was seen that some methods had proved effective, like blood transfusions from a survivor. But transfusions were still in their infancy. They were mostly performed directly from donor to patient and quite chancy since blood typing and matching were still a very new and largely lacunose practice. 

Aspirin

Flu normally attacks the more weakened members of a community: the sick and the old. The 1918 pandemic is unique in that the absolute risk of influenza mortality was higher in people younger than 65 and mostly raging from 20 to 40.
This has long been unexplainable, but recent studies have shown that the liberation of the selling of aspirin may have been a factor. 

Bayer had trademarked aspirin in 1899, but its patent expired in February 1917. New companies could now freely produced this lucrative medication, which became widely available in tins and bottles that didn’t typically contain warnings about doses and toxicity. Instructions were scarce when not lacking. 

Aspirin was known to be toxic in high dosage, but parameters were still unsure. Medical professionals still suggested up to 30 grams per day, a dose now known to be toxic (today, the general medical consensus is that doses above 4 grams are unsafe).
At the beginning of the 1900s, physicians treating serious conditions – such as rheumatic fever – had used aspirin to cure it but under strict monitoring. They would “push” salicylate until the first symptoms of toxicity appeared and then backed off. 

This was the regime in a hospital, but after aspirin became widely available, both doctors and people uneducated in the medical profession started to use it without proper monitoring. In Britain, for example, a dose of 15 to 20 grams was the recommended dosage, while the frequency was not given on the bottle. Cures of 6 grains of salicylate over 3 hours for several days was not uncommon. 
The excessive dosage, paired with ignorance of the unusual nonlinear kinetics of salicylate (unknown until the 1960s), predispose to accumulation and toxicity. Symons of aspirin poisoning includes hyperventilation and pulmonary oedema, or the building up of fluid in the lungs. The Spanish Flu infected the lower respiratory tract, produced acute respiratory distress. Aspiring poisoning, far from helping heal these conditions, may have worsened them. 

Taking all of this into consideration, researchers have recently put out the hypothesis that the wide, unregulated use of aspirin may have caused an abnormal number of deaths among young people. This sector of society was more open to new medicine and, therefore, more likely to use them. 

Face masks and other non-medical strategies of fighting the Spanish Flu

With the medical profession at a loss to stop the pandemic, local governments worldwide did what they could to prevent further spreading. It mostly included the method that had most proved effective over centuries of dealing with pandemics: social distancing. Places where a crowd could form, like amusement parks or cinemas, as well as schools, were closed. Many cities and regions enforced ‘no-spitting’ ordinances and encouraged people to use handkerchiefs or disposable tissues. In many places, people were required to wear masks in public. 

It was often a local effort, and therefore results were uneven. Some cities may enforce some of these practices and not others. And of course, people may abide or not, depending on their beliefs and personal inclination. 

Wearing face masks, for example, had uneven results. 
In the US, most people complied with it, especially during the war, because it was seen as the patriotic thing to do to help the soldiers at the front. Red Cross volunteers made and distributed surgical masks made of gauze to both soldiers and civilians. At the height of the pandemic, newspapers carried instructions to make masks, these too made of gauze.
But these masks were utterly ineffective if worn incorrectly, which very often happened. In Phoenix, for example, most people did wear a mask but poked holes in them so to be able to smoke. Many complained that masks were hot and stuffy.

One hundred years ago as today, the fight against the pandemic was a communal effort, involving the medical community and society at large. 

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RESOURCES

NCBI – The Origin and Virulence of the 1918 “Spanish” Influenza Virus
History – Spanish Flu
History – When Mask-Wearing Rules in the 1918 Pandemic Faced Resistance
Discover Magazine – 10 Misconceptions About The 1918 Flu, The ‘Greatest Pandemic In History’
The National WWII Museum of New Orleans – Medical Innovations: From the 1918 Pandemic to a Flu Vaccine
Oxford Academic – Salicylates and Pandemic Influenza Mortality, 1918–1919 Pharmacology, Pathology, and Historic Evidence
History Extra – Spanish flu: the virus that changed the world

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