Overview: The Flu Worldwide

"Prevent Disease" poster

This poster by the Rensselear County Tuberculosis Association encouraged people to do their part in preventing the flu by stifling their coughing and sneezing. (Rensselear County Tuberculosis Association, Troy, N.Y.)

What was the Spanish Flu?

Researchers consider the Spanish Flu to have been a type of Influenza A, specifically the Influenza A-H1N1 subtype. While there have been other pandemics caused by strains of H1N1, including most recently the “Swine Flu” of 2009, the 1918 Spanish Flu is considered to have been one of the most catastrophic flu episodes in recorded human history.

Who was affected by the Flu?

The Spanish Flu is believed to have infected around 500 million people worldwide between 1918 and 1919, and to have caused the deaths of between 50 to 100 million people (approximately 3-5% of the world population at that time). Soldiers and civilians, rich and poor were all affected alike.

One of the most disturbing aspects of the 1918 Spanish Flu was the high death rate amongst the young and otherwise healthy. This is thought to have been a result of the over-reaction of the immune systems of these individuals to the virus. In attempting to compensate and fight off the virus, their young and healthy bodies over-produced cytokines (substances excreted by the immune system) in the lung tissue. This would cause a build-up of fluid that often led to death from pneumonia. The rate of death among healthy young people who had survived other childhood diseases, such as measles and scarlet fever, contributed to public anxieties about the flu as it spread.

“It is noteworthy that the severe type affects with predilection young, strong...individuals, especially men. In them the prognosis is most unfavourable and the disease rapid.”

- Canadian Medical Association Journal November 1918

How did the flu spread?

The Spanish Flu circled the world in three waves.

The first wave of the flu, which occurred in spring 1918, went largely unnoticed by civilian populations. It mainly affected armies fighting the First World War in Europe, Asia and Africa.

The second and far more deadly wave occurred between August and late November 1918, with varying peak infection periods around the world. In British Columbia, and specifically in Smithers, peak infection appears to have lasted for approximately four to eight weeks between October 1st and November 30th 1918. 

The third and final wave of the flu is considered to have been between December 1918 and early 1919. Some cases of influenza in winter 1919/spring 1920 have been attributed to the Spanish Flu, although this "fourth wave" was nowhere near as lethal as those that preceded it.

Why 'Spanish' Flu?

The pandemic became known as the “Spanish” Flu around the world, not because it started in Spain, but because the Spanish press was the first to widely report on the spread of the epidemic. Spain, a neutral nation during the First World War, was one of the only countries not censoring its press at the time. Most other nations, including Canada, were tightly controlling the news in order to maintain public morale and support for the war effort.

Spanish Flu Patients at Camp Funston

This iconic image shows an emergency hospital at Camp Funston, Kansas, where those infected with the flu received care from doctors and nurses.
(Otis Historical Archives, Nat'l Museum of Health & Medicine)

Overview: The Flu Worldwide