The 1918 Flu Pandemic: Informing influenza research, 100 years later

Worldwide, the 1918 Spanish Flu pandemic swiftly killed approximately 50 million people and infected millions more – approximately 1/3 of the world’s population.

This pandemic was particularly unpredictable because it impacted otherwise healthy adults the most. The mortality rate among this group was 20 times greater than with the seasonal flu. Physicians could offer very little in the way of prevention or treatment – the most common prescription was bed rest and a careful diet.   

Many Canadians only think of the flu in the fall, especially when they are reminded to get their flu shots. However, dedicated scientists at the Public Health Agency of Canada’s National Microbiology Laboratory (NML) still refer to the memory of the 1918 flu in their day-to-day work. This is because the 1918 flu pandemic is sometimes called the “mother of all human flu viruses”.  In fact, almost all cases of influenza A have been caused by flu viruses that can be genetically traced back to the 1918 flu.

Origin story of the 1918 flu

No one knows for sure where on the map the 1918 virus actually came from, but Dr. Darwyn Kobasa, a scientist at the NML, agrees that like all other flu viruses, it likely originated in a bird. However, in order for the virus to make the jump from birds to human, it needed an intermediate host to allow the transmission to humans.

“Beginning as an avian virus,” Dr. Kobasa describes, “the 1918 virus most likely crossed into mammal hosts—possibly to pigs first, and then to humans—after an unknown period of adaptation.”

 “This period of adaptation,” he explained, “is one of the events that many flu researchers are now looking for with avian viruses—that is, mutations that would support a cross-over event to a new host species from birds.”

The NML’s 1918 virus research

Beginning in 2001, scientists at the NML partnered with scientists across the globe to reconstruct and understand the genetic makeup of the 1918 virus.

NML scientists found that the virus was very unique, even among the most severe strains of the human flu. In fact, when NML scientists needed to work with the 1918 flu virus directly, they could only do so in a level four containment lab. These state-of-the-art, high security laboratories are where scientists investigate deadly pathogens under the most secure conditions possible, in order to keep themselves and others safe from the virus.

Today, NML scientists are on the lookout for signs in current avian viruses that could possibly mutate and lead to a virus with the potential of causing another severe pandemic outbreak.

100 years later: Another flu pandemic?

The world has seen several flu pandemics, including in 1957-1958, 1968-1969 and 2009-2010, but none were as severe as the 1918 pandemic. Canadian researchers at the NML played a crucial role in decoding the 2009-2010 pandemic flu virus, isolating and replicating certain genes in the virus.

Thanks to scientists, like those at the NML, the world has made incredible progress through the use of flu vaccines and treatments which have helped to prevent and treat the severity of infections and diseases. Public health is in the hands of us all, and getting your flu shot is the best way to keep you and your family safe during flu season.

The 1918 flu pandemic remains a warning of what could happen if a completely new flu virus were to appear in the future. However, we have learned throughout history that no two pandemics are identical – we must be ready to adapt and adjust our public health advice based on situations as they develop.

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