On this day in medical history: The 100th anniversary of the Spanish Flu

By Paul Basilio, MDLinx
Published March 9, 2018

Key Takeaways

This year marks the 100th anniversary of the first US cases of Spanish Flu, an unusually deadly pandemic that exploited the desolation and upheaval of World War I to cause between 50 and 100 million deaths worldwide.1

This outbreak of influenza A H1N1 was unique in that the elderly were largely spared the brunt, but it was particularly deadly among healthy people aged 18 to 29. One reason for this is that an outbreak of an H3N8 flu virus in 1889 left a generation of children without a relevant antibody. A more closely related H1 strain was reported around 1900, which offered some protection for the youngest populations.2

In patients with Spanish Flu who died quickly, mortality was typically related to pneumonia via virus-induced pulmonary consolidation. Persons who lingered faced secondary bacterial pneumonia, and possible neural involvement. Many deaths have also been attributed to malnourishment.

The outbreak came in three waves during 1918 to 1920. In March 1918, company cook Albert Gitchell reported sick at Fort Riley, a military training base for World War I troops, making him the first recorded victim of the flu in the US. Within days, 522 men at the facility had reported in sick.3

The most deadly wave of the flu was the second in the fall of 1918.

In a typical outbreak, the patients who are most ill are usually isolated or secluded; therefore, those with mild symptoms tend to preferentially spread a milder strain of the pathogen. However, due to the circumstances of the war, the mildly afflicted stayed put while the severely ill were packed in trains and ships and sent to crowded field hospitals. There, they spread the deadlier strain of the virus.4

Worldwide death

While the accounting of the total mortality is imprecise, deaths around the globe attributed to the outbreak are estimated to include5-7:

  • India: 17 million
  • Iran: 902,400 to 2,431,000
  • United States: 500,000 to 675,000
  • Japan: 390,000
  • Italy: 390,000
  • Spain: 257,082
  • France: 240,000
  • Germany: 225,330
  • England and Wales: ~200,000
  • Portugal: 59,000
  • Scotland: 27,650 to 33,771
  • Ireland: 18,367
  • Norway: 14,676

About that name…

During war—and especially during a protracted, brutal war such as World War I—all sides look for an edge. While the disease had hit combat soldiers hard, various media outlets were facing strategic censorship.

Spain was neutral during the war, and as such its media was free to report uncomfortable facts. When a wave of disease hit the Iberian Peninsula in May 1918, it was front page news in Spain.

Historian Laura Spinney wrote in her book Pale Rider, “As time went on, and it transpired that there were not many local epidemics, but one global pandemic—it became necessary to agree on a single name. The pandemic became known as the Spanish flu and a historical wrong became set in stone.”3


  1. Burki TK. Lancet Respiratory Medicine. 2017;5(9)687.
  2. Vergano D. Mystery of 1918 Flu That Killed 50 Million Solved? https://news.nationalgeographic.com/news/2014/04/140428-1918-flu-avian-swine-science-health-science/. Accessed March 7, 2018.
  3. Spinney L. Pale Rider: The Spanish Flu of 1918 and How It Changed the World. Vintage Publishing; 2017.
  4. Gladwell, M. The Dead Zone. The New Yorker. September 29, 1997. 
  5. Mayor S. BMJ. 2000 Oct 7;321(7265):852.
  6. Kawana A, et al. Emerg Infect Dis. 2007;13(4):590-593.
  7. Mamelund, Svenn-Erik. Population, 2004;59(2):229-260.
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