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The 1918 influenza pandemic affected the whole world. Could it happen again?

The Great War had already taken so many. Then, as the war was in its death throes, a new enemy struck.

With symptoms so grotesque some called it the “black flu”, it was the disease that came to be known as Spanish influenza.

Over the course of about a year, up to one in three people in the world had been infected and 5 per cent of the global population killed.

It’s a death toll that’s hard to fathom, said University of Queensland influenza virologist Kirsty Short.

“This virus killed more people in 24 weeks than HIV killed in 24 years. This has been described as the greatest medical holocaust in history.

“The death toll was so severe that in some countries they actually ran out of coffins.”

So what was it that made the pandemic of 1918 so deadly, and in a modern world, with our knowledge of viruses and our advanced medicines, could something similar happen again?

Why ‘Spanish’ flu?

The 1918 pandemic didn’t start in Spain, nor was it most deadly there. But it’s where a lot of the press coverage of the pandemic came from.

Spain was a neutral party in World War I, and didn’t have the same wartime censorships in place other countries did.

“In contrast, countries that were at war, such as Germany and Britain, they didn’t really want to be talking about an influenza pandemic that was affecting their troops, because not only would it lower morale but it could also sort of make them seem more vulnerable to the enemy,” Dr Short said.

As to the virus’s true origins, it’s a murky story.

Some theories place the virus originating in France or England, others in China, but Dr Short said the best supported theory was that it broke out in Kansas in the US and was spread around the world by US soldiers.

Volunteer nurses from the tending influenza sufferers in Oakland, California, during the pandemic of 1918. (Wikimedia Commons)

.Flu happens every year. What made this one so deadly?

There’s a difference between seasonal flu and a pandemic, Dr Short said.

While seasonal flu constantly circulates and mutates, most people build up a level of immunity to it.

A pandemic happens when a new flu virus — one we have no or low pre-existing immunity to — enters the human population.

This can happen through infections in animals such as birds or pigs mutating into a form that makes them infectious to humans.

In the case of the 1918 virus, some people argue it came from birds; others say it was a bird flu that mixed its genes with a pig flu virus, but Dr Short said the exact pathway of animal to humans remains one of the biggest mysteries of the pandemic.

It’s thought that one of the reasons the flu was so deadly among healthy adults was because their immune systems were more active and resisted the virus more vigorously, according to Geoffrey Rice, historian at the University of Canterbury and author of a book on the pandemic in New Zealand.

“These poor people literally drowned in their own bodily secretions,” Professor Rice said.

“Their lungs just filled up with their own bodily fluids. And because of the inability of the lungs to exchange oxygen their skin lost its normal healthy pink appearance and turned a sort of dusky purple or black.

“My grandmother always referred to this as the ‘black flu’ because the bodies turned black.”

In this way, it bucked the usual trend of influenza deaths, which usually occur in the obviously vulnerable populations of the very old and the very young.

As well as the aggressive way the 1918 virus hijacked the immune system, it was transmitted further and wider than it perhaps otherwise might have been because of something else happening in 1918: World War I.

“A pandemic at the time of war is never good, no matter what war, no matter what pandemic,” Dr Short said.

Movement of troops around the world played a big part.

“It’s also about living conditions. You have soldiers who were living in barracks in close proximity, so that’s not only a perfect breeding ground for spreading influenza, but it’s also a perfect breeding ground for spreading secondary bacterial infections, which were actually the predominant cause of deaths during the 1918 pandemic,” she said.

“You also have issues associated with information communication. You had this question of people not wanting to report the pandemic in its initial phases because they don’t want to dampen people’s morale during a war.

“The other thing to consider is that in a war people probably aren’t at their healthiest. There’s limited food available for both soldiers and civilians — so that can only serve to make any sort of infectious disease worse.”

Pandemic panic

Board of Public Health Victoria leaflet on “Spanish” influenza. (Wikimedia Commons: Public Records Office of Victoria)

The official line in US newspapers was that the so-called Spanish influenza was just ordinary flu by another name, and that you had nothing to fear if proper precautions were followed, according to historian and author John Barry.

In contrast, people were seeing with their own eyes their neighbours and loved ones dying with a day or so of first symptoms, “sometimes dying with horrific symptoms”, Mr Barry said.

“The worst were probably being bleeding from the nose, mouth, ears and eyes. So people instantly knew they were being lied to. A real panic and terror erupted.”

The backlash to this disconnect between the official line and what people were witnessing meant many people suffered even more, he said.

“In some cases … influenza victims were starving to death, not because they didn’t have any food available, but because their neighbours or even in some cases their family was afraid to bring them any food.”

The pandemic didn’t actually reach Australia until it was in its less severe third wave at the beginning of 1919.

Communication about the dangers of the flu strain was more forthright than those in the US.

By the end of 1919, more than 12,000 Australians had died from the disease. Sydney was hit hardest — it’s estimated more than a third of the city was infected.

“A danger greater than war faces the State of New South Wales and threatens the lives of all,” read a government proclamation in the Sydney Morning Herald on February 3, 1919.

“Everyone shall wear a mask.

“Those who are not doing so are not showing their independence — they are only showing their indifference for the lives of others — for the lives of the women and the helpless little children who cannot help themselves.”

But while Australia suffered it wasn’t to the same extent as much of the rest of the world, Dr Short said.

“Australia, because of our strict maritime quarantine, we really missed out on the first wave and most of the second wave,” she said.

“So we really only got the slightly less virulent third wave of the virus.

“That may help to explain why Australia had one of the lowest influenza death rates of any Western nation.”

Around the world, a primitive understanding of how disease spread meant unusual remedies abounded, Professor Rice said.

“City councils had civic clean-ups, to get rid of rubbish, because a lot of people still thought in terms of the old miasmatic theory of infectious disease that infections were caused by bad smells and rotting vegetation and things like that,” he said.

“Disinfecting or fumigating places — in New Zealand the remedy was to go to an inhalation chamber and suck in a vaporised 2 per cent zinc sulphate solution. This was basically a crude mouthwash disinfectant.”

Demonstration at the Red Cross Emergency Ambulance Station in Washington, DC, in 1918. (Wikimedia Commons: Library of Congress)

.Could it happen again?

In 1918, no-one even knew what a virus was. They didn’t have antibiotics to treat pneumonia infection and people were often being treated at home or in field hospitals — the resources were relatively primitive.

But as to the question of whether another pandemic could be similarly deadly in modern times, some experts say it’s possible, even probable.

One of the people working to mitigate this is James McCaw, a mathematical biologist at the University of Melbourne. He uses maths to track how diseases spread through populations and takes those insights to forecast how they might spread in the future.

Part of his work has involved modelling the 1918 pandemic using historical data.

“The 1918 flu pandemic was a spectacularly destructive event — a global event where some 20 to 100 million people perhaps died in a period of just nine months all around the world,” he said.

“We have pretty good data on what happened back then. A lot of the public health agencies recorded very detailed information on even town by town, or city by city, basis.

“What we see from the data is some really fascinating patterns. So we see multiple ways that the flu spread and then it died away, it came back even worse in the northern hemisphere’s autumn wave. And then it went away and then it came back again.”

Another flu pandemic is inevitable, Professor McCaw says, simply because flu viruses are so prone to mutate. Eventually, we’ll encounter another virus that we have low immunity to and it will spread rapidly.

“That’s inevitable. When it will happen is anybody’s guess,” he said.

“It’s just like the lottery — if you buy tickets all the time, well, at some stage someone’s going to win, but any individual, you never know when it will be, because it’s random chance.

“So yes, there will of course be another influenza pandemic — it might be next week or it might be in 25 years’ time or it might be in 80 years’ time. We’ve got no idea, to be honest. And so what we do is monitor for things that we know we would be worried about.”

Some of those things are disease transmission in the types of animals that are natural reservoirs for influenza, which are mostly water birds. Others are particular strains of virus that can have high mortality rates when they do occasionally infect humans.

These flu forecasts are imprecise — more like the weather forecasts of 30 years ago — and intense monitoring in one high-risk area doesn’t mean something can’t come out of left field, like the 2009 swine flu pandemic. But they’re better than nothing.

“By building those early forecasts for influenza, we will then be able to make them better and better,” Professor McCaw said.

“Eventually we’re hoping to get to a stage where we have incredibly accurate influenza forecast systems that can really help our public health officers and government make good decisions on how to respond to these diseases.”

As to whether a modern outbreak of a flu like the 1918 strain could be as deadly in modern times, Dr Short said that depends on how good surveillance is and how we respond.

That includes monitoring strains to ensure there are adequate supplies of vaccines available — it takes a minimum of four months to create a new vaccine, she said — and ensuring hospitals and healthcare services are prepared.

Another possible stumbling block is antibiotic resistance.

Re-analyses of autopsies of people who died in 1918 show that the majority of people who died didn’t die from the flu virus itself, but from secondary bacterial infection.

This should be concerning to us in modern times, Dr Short warned.

“Obviously 1918 it was very concerning because there were no antibiotics available. And you would think, OK, well today that’s not a problem because we’ve got antibiotics,” she said.

“But the reality is that we’re looking at a future where antibiotic resistance is going to be mean that antibiotics are ineffectual.

“So when people are talking about antibiotic resistance … this is not just important for the bacterial infections itself, but it also will have a big impact on our preparedness for future influenza pandemics.

“Because it’s likely that in these future influenza pandemics, secondary bacterial infections will continue to play a major role in disease severity.”

The quest for a universal flu vaccine remains a tantalising shimmer on the horizon. It’s not a completely crazy idea, Dr Short said, and it could happen within our lifetimes. But to ensure we live long enough to see whether it eventuates, we need to be prepared to meet pandemics now.

This story was put together with the help of the Health Report, Rear Vision and Ockham’s Razor.

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