What was the Spanish flu and what clues does it give us about Coronavirus?

Despite its name, the Spanish Flu was likely not Spanish at all.

Several theories have been put forward with no definitive cause confirmed even a century after the devastating pandemic, which killed anywhere between 50-100 million people.

The origin is either; in France, among soldiers fighting in the trenches, or a ranch in the US state of Kansas. Chinese labourers brought over to Europe to help the war effort have also been cited as a possible source.

Part of that mystery lies in the circumstances of the war. Neither side wanted to give its opponent any indication of the scale of the epidemic, fearing it would be used for propaganda purposes. That made it harder for scientists to later determine where and how it started.

The unfortunate legacy of giving the virus its name, therefore, landed on the lap of neutral Spain.

Because its media was unencumbered by wartime restrictions, Spanish journalists were the first to describe the impact this strange new disease was having. The rest of the world picking up on these reports for the first time, therefore, gave the disease the name ‘Spanish flu’.

A potent killer

The First World War killed up to 40 million people at its highest estimates, and a large number of these were killed by the Spanish flu.

Battlefield hygiene meant little could be done to counter the spread of the disease, as most soldiers lived in cramped trench conditions on the front.

According to Stanford University academics, more US soldiers died of the flu in Europe than fell in combat.

When infected soldiers went home, they took the flu with them, helping speed up its rampage across the globe.

It is believed that up to a third of the world’s population at the time, or 500 million people, were infected by the flu. Of these between 10 and 20 percent ending up dying of the disease.

The death toll of up to 100 million people makes the Spanish flu the deadliest pandemic in human history, even more so than the medieval Black Death.

In the years following the Spanish flu outbreak, scientists identified the virus as an avian variant of the common H1N1 flu causing virus. Similar pandemics occurred at several points during the following century but none as deadly - a notable example was the 2009 Swine flu pandemic, which had a mortality rate of approximately 0.001 percent, according to US researchers.

The Spanish flu was especially lethal among infants, young people between the ages of 20 and 40, and the over 65s, according to the Center for Disease Control and Prevention (CDC).

With no vaccines available to tackle its spread, the measures introduced were similar to the ones we see today with the novel Coronavirus crisis, though the application was not uniform.

People were advised to maintain strict hygiene methods and practice social distancing methods.

The pandemic eventually petered away as its victims either died or gained immunity.

Why was it so deadly?

What made the Spanish flu virus so deadly is still a matter of debate a century later, and an even bigger mystery is why the mortality rate associated with the virus fluctuated with age groups.

According to the US National Institutes of Health, the virus was particularly lethal since the virus embedded itself in the lungs, thereby lowering their resistance to secondary bacterial pneumonia.

That is not to disregard the contributory factors, such as lack of knowledge about viral infections and disease management.

Doctors tackling the ongoing Covid-19 outbreak can rely upon antibiotics to treat secondary infection, as well as other drugs and techniques. Many of these did not exist in 1918.

The CDC outlines the disease management technologies not available at the time of the Spanish Flu outbreak:

“Influenza vaccines did not exist at the time, and even antibiotics had not been developed yet. For example, penicillin was not discovered until 1928. Likewise, no flu antiviral drugs were available. Critical care measures, such as intensive care support and mechanical ventilation also were not available in 1918.”

Knock-on effects

The Spanish flu was also followed by inexplicable and seemingly unrelated increases in other physical illnesses.

In 2009, researchers found that children born during the height of the pandemic in 1918 and 1919 were at a 20 percent higher chance of getting a heart attack at the age of 60 than others born upto a few years earlier.

Men born during the affected years were on average shorter than others in their age group. 

Researchers cited by Time Magazine found that those born the year the Spanish flu pandemic was ongoing had higher rates of disability and performed worse academically.

While the historic and scientific contexts of the Spanish flu are relatively far removed from the current pandemic, there are lessons to be gleaned.

Just as the movement of soldiers facilitated the spread of the virus in 1918, Covid-19 relies on our globalised system of travel to reach far off places.

By introducing effective quarantine methods, and upholding high standards of hygiene and disinfection at transport hubs, the spread of the virus can at least be slowed.

Although not as lethal as the Spanish flu, the Coronavirus still carries the potential to cause mass death, as well as disrupt the global economic system.

The Spanish flu pandemic lasted for two years during a period of economic devastation caused by the First World War, and the Coronavirus pandemic is happening a decade after the Great Recession, with many economies still precariously perched.

All these effects could be further compounded by subsequent outbreaks of the Coronavirus in the winter.