100 years ago, the Spanish flu killed millions. Could it happen again? – National

The First World War is one of the deadliest conflicts in human history. But not as deadly as the flu.

The Spanish flu, which reached its peak in the fall of 1918, killed somewhere between 20 million and 40 million people, with some claims reaching as high as 50 million. In Canada, it killed around 55,000, mostly young adults.

The virus spreads rapidly around the globe.

And now, 100 years later, scientists are still looking back at the pandemic and what can we tell you about how to prepare for the next one.

Because the question is not it will happen again, they say, but when.

A single virus

The Spanish flu was unique in a number of ways. Unusually, it was young, more healthy than the elderly, most likely, said Dr. Gerald Evans, Chair of the Division of Infectious Diseases and Professor of Medicine at Queen's University.

In the late 1990s, researchers were able to re-create it, using material from a frozen victim's corpse found buried in the Alaskan permafrost.

They were able to learn a few things about the virus itself. First, the re-created virus was unusually deadly, killing test in just a few days. It also affects more than just lung cells, which is unusual.

READ MORE:
Flu season this year could be mild – but you should still get your flu shot

The Spanish flu was also brand new at the time, Evans said. It was a "recombined" virus, meaning, "There were pieces of it from a bunch of different viruses, influenza viruses, that came together to create the unique H1N8 strain that it was."

The result: people did not have much immunity to it, with deadly consequences.

New flus

The 1918 flu virus was unique, but Evans said.

"It's really just a throw away from the genetic dice that we've had a Spanish flu that's yet popped out."

Lots of animals, like chickens and other birds, carry flu viruses, though they are not readily available to humans.

That's where animals like pigs come in, he said. Pigs can catch flu pig, human flu, and they can catch avian flu, and they can mix them both to create a brand-new virus capable of infecting humans.

WATCH: What can you expect this flu shot can help

The 2009 flu pandemic was a re-badortment of different types of swine, avian and human flu strains, he said. "It was a new virus that nobody had seen in the human population before."

"We were just fortunate that it did not kill people."

Dealing with the flu

In many ways, the world is better-prepared to deal with a pandemic than it was in 1918.

"Almost everywhere in the world, and Canada is a good example of it, we have had some plans in place," said Evans.

A paper published in early October in the journal Frontiers in Cellular Infection and Microbiology found that global influenza surveillance programs are constantly monitoring for influenza, and they are acting on information – by slaughtering infected poultry, for example – to prevent them from spreading.

READ MORE:
When – and for how long – is your flu contagious?

And our medical capability and understanding has grown, the paper found, so that the flu is easier to recognize and receive better care while sick.

Many countries, including Canada, also have antiviral stockpile drugs that can be used on patients, Evans said, hopefully buying time in a pandemic.

New challenges

But there are new risks, too. "We now face new challenges including an aging population, people living with underlying diseases including obesity and diabetes," wrote study co-author Dr. Carolien van de Sandt of the Peter Doherty Institute for Infection and Immunity at the University of Melbourne.

"In 1918, a large proportion of the elderly population was, to some extent, protected from a severe infection as a result of pre-existing immunity that they acquired during an infection with a previous influenza virus that resembled the 1918 virus," said another co-author, Katherine Kedzierska, also of the Doherty Institute. She is not sure that it will be the case during future pandemics.

"What we know from the 2009 pandemic is that obese and diabetic people were significantly more likely to be hospitalized with, and die from, influenza," said co-author Dr. Kirsty Short of the University of Queensland. "We also know that people with obesity have an adverse reaction to the seasonal flu virus, which leaves this population group at risk of severe disease."

Air travel also means a virus can spread from one continent to another in just hours.

Pandemic life

Evans hopes that in a severe pandemic, everything goes according to plan. But he does not know that there is a lot of potential for something wrong. This could mean a lot of disruption in people's day-to-day lives.

If it says it's a usual supposition for pandemic planning, it would have a big impact.

READ MORE:
'You can never be completely prepared' How scientists spot the next pandemic

Imagine if you meet in your day sick, he said. "All of a sudden you're not going to have deliveries of food, of gasoline, of the batches that we kind of take for granted in our day-to-day lives."

Maybe schools are closed so that kids do not transmit the virus, meaning even healthy parents, he said.

Despite that, he's cautiously optimistic.

"Pandemic plans are in place. All countries have them. Here in Canada all countries and provinces have them. We've stockpiled stuff. We're pretty sure we're ready in case it hits. "

Canada just needs to "Let us know that we can not kill a lot of people, that we can distribute our antivirals around the world and that we can get a vaccine that we can minimize that impact," Evans said.