“We have incredibly good disease surveillance in place around the globe,” says Dr Peter Barlow, an associate professor at Edinburgh Napier University Image Credit: Supplied

A cough. A sneezing fit. A sudden nosebleed. One by one, soldiers at Etaples in northern France began to show symptoms. And in the dying days of the First World War, soldiers mingled with others. German prisoners. American soldiers returning home to the United States.

It was the perfect incubator for a deadly form of influenza. A hundred years ago, Spanish flu killed more — many millions more — than those who died in the fighting in the trenches on the Eastern and Western fronts.

“Spanish flu was one of the worst pandemics in modern times,” Dr Peter Barlow tells Weekend Review. “It cost anywhere in the region of 20 million to 100 million deaths worldwide and around 500 million infections. In terms of severity, this was one of the most serious outbreaks of disease the world has ever seen.”

Dr Barlow is a spokesperson for the British Society for Immunology and is Associate Professor of Immunology and Infection at Edinburgh Napier University. The British Society for Immunology is a membership organisation that represents scientists and clinicians who study how the immune system functions in health and disease, and has approximately 3,500 members who work in hospitals, universities and research institutes worldwide.

Consider the arithmetic of the pandemic. About a third of the population of the world was infected. Of these cases an estimated 10 per cent to 20 per cent died. In turn this implies that nearly 3 per cent to 6 per cent of the entire global population died. These are incredible figures, even if historians calculate that the medieval Black Death was even worse.

Because nations involved in fighting in the First World War have censorship details in place, Spain was neutral and could report freely on the spread of the pandemic — hence Spanish flu.

There simply hasn’t been a modern equivalent to the pandemic which infected one-in-three of the world’s population in 1918.

Is there a modern equivalent to the 1918 pandemic?

“Sars — there hasn’t been any new case since 2004,” Dr Barlow says. “It caused around 8,000 infections and around 800 deaths. I don’t believe that there’s a strong likelihood of it emerging again, but if it does, there will need to be a containment action in place to prevent spread.”

And even when it comes to the Avian flu, there isn’t a direct comparison. “If you compare 1918 pandemic flu to avian influenza, avian influenza doesn’t really tend to infect humans. It’s quite rare for Avian influenza to cause a human infection, and it usually happens when a human has been in close contact with an infected bird and has been in contact with quite substantial amounts of the virus. So, because it’s less likely to be transmitted to humans, it’s also less likely to be transmitted between humans, so that means it’s less likely to spread among human population.”

And even if there was to be an outbreak of a similar pandemic, there are systems in place to prevent the spread now.

“Thankfully, we have incredibly good disease surveillance in place around the globe,” Dr Barlow notes. “We have research that has created vaccines in preparation for that type of outbreak, there’s already vaccines being created for Avian influenza, and what that means that if there is a situation where that does virus does become transmissible between humans, that we’re already a step ahead, we can use those vaccines to create global vaccines.”

The nearest equivalent to the Spanish flu would have been the effect of the small pox virus on indigenous American people carried by European travellers. It’s estimated between 400 million to 500 million died from the virus that has largely been eradicated now.

“The main thing with the 1918 flu pandemic was that it came at a time at the end of the First World War when troops were being deployed around the world, so scientists think that’s part of the reason this virus moved around the world so quickly and so effectively was because of the movement of people around the world,” Dr Barlow says. Indeed, it’s a challenge modern immunologists are familiar with now, given the prevalence of air travel.

“There is controversy about screening at airports and how effective it is,” he notes. “What I say is that the main way you can control an infection is through vaccination. That’s absolutely the most effective way of controlling any viral spread. If there’s a vaccination available, then you roll it out as quickly and as effectively as possible.”

So just how bad was the 1918 virus?

“It was quite a severe infection in comparison to some modern influenza infections,” Dr Barlow says. “The normal symptoms of influenza are fever, shortness of breath. But with the 1918 flu, there were other symptoms like vomiting, nose bleeds and it was found that the virus caused haemorrhage in the lungs. And modern experiments have identified that this virus could create or induce very severe inflammation in the lungs. So, flu doesn’t cause a severe inflammation in the lungs, but the 1918 virus did cause a very severe inflammation in the lungs and lots of cell death. What that meant was that the physical impact was quite severe. People are essentially haemmorhaging in their lungs and having nose bleeds and very high fever — so it must have been quite a terrifying experience to either suffer from that virus or being in the same household of someone who was suffering from it.”

Essentially, many patients drowned in their own blood. “It’s very dramatic way of saying it,” he says. “With flu, you do get a buildup of fluid in the lungs — edema. This virus also causes inflation in other areas of the lungs, like the alveoli or the deeper reaches of the lungs.”

Dr Barlow has spent time at the Centers for Disease Controls (CDC) in Atlanta, reconstructing the spread of the Spanish flu virus. “It was an airborne virus,” he says. “When you contract the flu one of the first signs is a sneeze or cough and that’s an incredibly effective way or creating aerosols that contain the virus and then other people that are near you either inhale those aerosols or they can touch a surface that has been contaminated with the virus and then inhale that. They are several different ways that the virus can be transmitted, coughing, sneezing — an airborne virus, that’s how you contract it.”

And when it comes to annual flu shots, Dr Barlow is adamant that as many people as possible should get flu vaccinations each year. “My perspective is that there is no reason not to get a flu vaccination,” he says. “We know that every year it isn’t 100 per cent effective but it is absolutely the best way we have of preventing the spread of flu — and it’s been shown that the flu vaccine can reduce the risk of a child of infant dying from an influenza infection, so the more people that are vaccination against flu, the less people are going to catch it. So, from my perspective, I strongly, strongly encourage anyone to vaccinate themselves and their children against flu.”

It’s a philosophy that also applies to childhood vaccinations for measles, mumps and ruebella (MMR). “Some people have suggested that there is a link between autism and the MMR vaccine,” Dr Barlow says. “To my knowledge, that link has never been determined and the MMR vaccine is the best possible way of preventing a child from contracting measles, mumps or rubella.”

Even though the Spanish flu pandemic is now a century ago, there are still lessons to be learnt for today’s immunologists

“There has been a lot of research that has reconstructed the 1918 flu virus and there’s been a lot of experimentation done with that virus, so we have a much better understanding of why that virus was transmitted and caused the disease that it did,” he says. “That’s not to say that there aren’t still areas of research that need to be done on that virus, but when you get that information and you do that research and understand how a virus can do so much damage, you can then use that information to create vaccine candidates. And you can also use that information to predict when you see a new virus how much it going to travel around the world and how pathogenic or damaging to humans it’s going to be. That’s why it’s so important that we study these historical pandemics so that we can use that data to predict what will happen in future pandemics.”

Mick O’Reilly is the Gulf News Foreign Correspondent based in Madrid.