The influenza pandemic, otherwise known as the “Spanish Flu,” of 1918 had three successive waves and killed about 50 million people in only a couple of years. To put this outbreak into context, it resulted in more deaths than the entirety of the First World War. Doctors were able to do little and countries, blaming others, closed borders. Also affected, were the combatant militaries of the nations engaged in the First World War.[i] As a result, a retrospective of 1918-1919 provides a glimpse of the impact of this pandemic upon the various combatant military forces of that time. From that one can discern some of the choices that modern militaries must grapple with during an outbreak. Accordingly, when considering the impact of coronavirus disease (COVID-19) on North Atlantic Treaty Organization (NATO) armed forces, these events of a century ago offer relevant historical lessons for Alliance militaries.

“Spanish Flu” 1918 - 1919

There are many similarities between the spread of the influenza pandemic of a century ago and that of COVID-19 today. The influenza pandemic of 1918 may have crossed over from animals, perhaps avian or swine. Additionally, some historians argue that the misnamed Spanish flu, initially believed to have come from Spain, might have originated in China.[ii] Like the current day predictions for COVID-19, there were several “waves” of the Spanish Flu, three in all. Due to the concentrations of military personnel, the troop movements associated with the War, and redeployments at the end of the fighting this flu, the transmittal occurred in a similar globalized fashion to that of COVID-19. Also, like COVID-19, the Spanish Flu was extremely virulent, killing many.[iii]

Medical investigations conducted during the First World War and immediately afterwards concluded that frontline conditions, along with the closeness of military life, likely exacerbated the effects of the disease. Influenza connected illness and death among military personnel were attributed to specific war-related conditions. These included: (1) overcrowding; (2) unsatisfactory hygiene; (3) inadequate clothing; (4) exposure to adverse climatic conditions; (5) and, badly vented accommodations.[iv]

Resultantly, none of the combatants engaged in Europe were spared the impact of influenza. The highest illness rate was amongst the United States Army, which recorded over one million cases in Europe and in training camps. In comparison, in France during 1918, the British Expeditionary Force documented 700,000 cases, the French Army had 436,000 sick, and the German Army recorded 700,000 instances of influenza.[v]

The first Western Front influenza wave in Spring 1918 made significant inroads in the war-tired forces of three battling participants – the French, the British, and the Germans. The French were evacuating 1500-2000 cases per day, while the British were suffering similarly debilitating impacts. The German commander General Erich von Ludendorff observed: “Influenza was

rampant … It was a grievous business having to listen every morning to the chiefs of staffs’ recital of the number of influenza cases, and their complaints about the weakness of

their troops if the English attacked again.” This wave diminished by the Summer, but for the Germans the damage had been done. Von Ludendorff attributed the collapse of their Spring offensive to the devastating impact of the disease upon his army. While attaching this failure to the flu is debateable, it is likely safe to say that influenza undoubtedly weakened the German army at this critical period. This trend continued for all belligerents during the Fall with the second wave of the influenza, which had a significant impacts on the Americans.[vi]

By October 1918 within the American Expeditionary Force (AEF) influenza patients, considered non-battle casualties, were by far the largest number of hospitalized soldiers. AEF statistics for 1918 indicate that over 340,000 members of the AEF were admitted for influenza, while throughout the same period about 227,000 were admitted for combat injuries. This second wave of the pandemic arrived at the worst possible time for United States military operations; the diseased peaked within the AEF during the Meuse-Argonne Offensive. For the AEF this series of operations constituted the major campaign of the First World War and the impact of the disease was considerable. Transportation of sick soldiers overwhelmed lines of evacuation and filled hospital beds – many were rendered non-effective due to illness and thousands died. This flu negatively impacted on American operational effectiveness by diminishing the forces available for military activities and reduced morale. Furthermore, it distracted United States political leaders and AEF commanders from winning the War, to fighting disease – an argument that can likely be made for the other wartime participants as well. Despite best efforts otherwise, influenza killed more American military personnel than wartime combat. [vii]

With the end of European fighting in November 1918, the movement and demobilization of these vast armies further spread the virus and contributed to the pandemic’s third wave. This last surge of flu eventually diminished and disappeared over Winter 1919. The negative influence of influenza upon the First World War militaries was extreme. Not only did it create many ill and dead amongst young military and potential military personnel, it also affected civilian and military leaders, and civilian labor, who were necessary to support the fighting forces. Moreover, it negatively influenced morale, training, and troop reinforcement, along with general military movement and maneuver. Another result of the virus was that medical facilities were inundated with patients, eliminating their capacity to deal with combat related casualties. In addition to the negative physical and morale aspects of this pandemic there were also negative psychological characteristics ranging from depression, through to delusions and insanity, to suicide. In this fashion, military effectiveness was undermined by influenza.[viii]

Protecting the Force and Assisting Civilian Authorities

From these adverse consequences there are numerous examples how First World War militaries tried to protect their forces. For instance, the French Army’s approach to prevention and mitigation would not be out of place today. Basic hygiene measures, while challenging in combat conditions, were ordered and enforced. Measures were taken to evacuate and quarantine the ill while being careful to always separate them from others. Additionally, all transport and medical facilities that they passed through were cleaned and disinfected.[ix]

While it would be difficult to isolate or quarantine soldiers deployed on operations, a form of “social distancing” was employed as a method to prevent the spread of disease. The German Army recognized the connection between the spread of the disease and how closely troops were quartered, stressing that the amount of influenza cases in a unit directly depended on the type of accommodation for the soldiers. Closely accommodated units had a large percentage who became ill, but those who where not densely put together had much lower rates of infection. It was also noted that the lowest infection numbers were among the officers, who were able to obtain single accommodations.[x]

With the exigencies of total war, military and civilian medical systems were intertwined; the British had a system of military pathology that connected clinical laboratories in England with military hospitals in Belgium and France. Vaccines were made and tested in several militaries including Britain, Canada, and the United States. For instance, the United States Army Medical School produced and disbursed two million doses of trial vaccine between October to November 1918. Regrettably, due to a lack of understanding of the pathology of the disease and emerging vaccine production capabilities, no conclusive results were obtained. In conjunction with this production of experimental vaccine, the military was the ideal setting in which to trial these serums due to pools of available test subjects, controlled conditions, and systemic reporting of trial results. [xi]

In Canada and England, Canadian military doctors mirrored and contributed to the implementation of public health policies and measures. This included quarantine, vaccination, and utilization of gauze masks. However, cooperation between Canadian military doctors and their civilian counterparts was not uniform and was sometimes perceived by the military as inimical to the war effort.[xii]

In Europe and North America further attempts were made to help civilian authorities. An instance of this were French military doctors who attempted to assist with treating influenza within the civilian population as fully as wartime circumstances allowed. Similar efforts to aid the civilian population were evidenced in the United States.[xiii]

Military Implications for Pandemics

Like the lessons identified from 1918 – 1919, NATO militaries responding to COVID-19 took similar actions to protect themselves, conduct operations, and support their civil authorities. Italy, one of the NATO members hit hardest by COVID-19, provides examples of this pandemic response. The Italian Armed Forces assisted the government in implementing containment measures and received high levels of support from the Italian people.

Italy’s military helped civil authorities in multiple areas related to medical assistance. This support included: (1) deployment of military medical task forces to hospitals; (2) provision of medical airlift and transport, equipped with biological containment systems; (3) and, secondment of military doctors and nurses to respond to the outbreak, plus temporarily hiring over 200 doctors and nurses to increase military support capability. Furthermore, over 1,400 military land vehicles have been used for transport, and over 1,000 beds have been provided by field hospitals. Two field hospitals were set up in the cities of Piacenza and Crema, both located in the most severely afflicted northern part of the country. The two military hospitals are now integrated into the national health service and fully support local civilian hospitals. By April 2020, over 20,000 Italian troops from all services were directly engaged in COVID-19 response operations.

Also, with roughly 7,000 Italian military personnel employed in 24 missions and 16 operations in 24 different countries, the Italian Ministry of Defence made several changes in supporting these international commitments. Italian forces deployed outside the country were issued protection kits and reduced to a minimum contact with local populations. Operational activities were diminished in Kosovo (NATO Kosovo Force) and Lebanon (United Nations Interim Force in Lebanon). Some personnel were withdrawn from NATO operations in Iraq and Afghanistan. Italian military training in Iceland was postponed. At the same time, all domestic Italian forces not engaged in operations related to COVID-19 were subject to the same movement restrictions as the civilian population to protect these uncommitted forces from infection.[xiv]

This Italian force posture was mirrored by other NATO members. For example, the United States services took on similar types of missions to assist the civilian authorities, while at the same time maintaining international operational commitments and protecting their forces from this virus. Furthermore, the requirement for force protection was highlighted within the United States and French navies with very public disclosures of instances of COVID-19 illness within their carrier fleets.[xv] These trends have continued throughout the pandemic.

Quo Vadis?

It would be difficult to suggest that the Spanish Flu had a powerful influence on the outcome of the First World War. Influenza struck all European combatants simultaneous and weakened them similarly, while at the same time outbreaks in their home nations correspondingly degraded their national support. However, the negative impacts of influenza on the fighting forces where myriad and made war, always a difficult endeavour, that much harder. Politicians and military commanders were distracted, the morale, physical, and mental well-being of military personnel were adversely affected, troop strengths and preparedness were reduced, while maneuver and movement restricted. On top of this, the capacity of the medical system to treat battle casualties was severely reduced as the medical treatment and evacuation chain were overwhelmed with soldiers struck down by influenza.

At the same time, it is evident that there were measures taken to reduce illness, even amid operations. Plus, the military used its resources, where such ability existed, to support their home nations in battling the Spanish Flu. This ranged from medical research, through manufacture and transport of supplies, to the testing of vaccines and provision of medical services to civilians.

Accordingly, in the context of COVID-19 and possible future pandemics, NATO commanders need to consider how they will simultaneously conduct operations while protecting and preserving their forces for future activities. Also, needing deliberation is the foci of military support to civilian authorities and in what way NATO forces can be best employed to alleviate pandemic effects. Although the First World War provides valuable insights, the lessons identified during the Spanish Flu pandemic 1918 - 1919, along with those gained from the global outbreak of COVID-19, need to be refined and inculcated in policies, programs, and doctrine, particularly pertaining to Non-Article Five Crisis Response Operations. It is only by this systemic inculcation of knowledge hard won by fighting these viruses can NATO transform this information into lessons learned useful in countering future pandemics.

 This KCIS Insight is an early version of what was later published as “The influenza pandemic of 1918: military observations for today,” in NDC Research Paper 09 - COVID-19:  NATO in the Age of Pandemics, edited by Thierry Tardy (Rome: NATO Defense College Research Division, 2020), 61-69.

Howard G. Coombs is an Associate Professor of History at the Royal Military College of Canada and the Deputy Director of the Queen’s University Centre for International and Defence Policy, both in Kingston, Ontario. He is also a part-time Canadian Army reservist with the Office of the Chief of Reserves, located at the Canadian Armed Forces National Defence Headquarters. Coombs received his PhD in Military History from Queen’s University. His research interests are Canadian professional military education, in addition to Canadian military operations and training.

Endnotes

[i] See Laura Spinney, Pale Rider: The Spanish Flu of 1918 and How It Changed the World (New York: Public Affairs, Hachette Book Group, 2017).

[ii] Mark Osborne Humphries, “Paths of Infection: The First World War and the Origins of the 1918 Influenza Pandemic,” War in History 21, no. 1 (January 2014): 58.

[iii] The origins of the 1918 pandemic are still under study. Jeffery K. Taubenberger and David M. Morens, “1918 Influenza: the Mother of All Pandemics,” Emerging Infectious Diseases 12, no. 1 (January 2000): 16-17; and Peter C. Wever and Leo Bergen, “Death from 1918 Pandemic Influenza during the First World War: A Perspective from Personal and Anecdotal Evidence,” Influenza and Other Respiratory Viruses 8, no. 5 (1 September 2014): 538.

[iv] J.S. Oxford, et al, “World War I May Have Allowed the Emergence of ‘Spanish’ Influenza,”

The Lancet: Infectious Diseases 2, no. 2 (February 2002): 113.

[v] Peter C. Wever and Leo Bergen, “Death from 1918 Pandemic Influenza during the First World War: A Perspective from Personal and Anecdotal Evidence,” Influenza and Other Respiratory Viruses 8, no. 5 (1 September 2014) : 539; and Olivier Lahaie, “L’épidémie de grippe dite ‘espagnole’ et sa perception par l’armée française (1918-1919)” Revue historique des armées 262 (2011): 6.

[vi] Peter C. Wever and Leo Bergen, “Death from 1918 Pandemic Influenza during the First World War: A Perspective from Personal and Anecdotal Evidence,” Influenza and Other Respiratory Viruses 8, no. 5 (1 September 2014): 539-540; Christine M. Kreiser, “History Net: 1918 Spanish Influenza Outbreak: The Enemy Within,” accessed 15 April 2020,  https://www.historynet.com/1918-spanish-influenza-outbreak-the-enemy-within.htm; and Robert Farley, “Coronavirus is a Killer (But the Spanish Flu Killed Five Times More People Than World War I),” The National Interest, last modified7 March 2020, https://nationalinterest.org/blog/buzz/coronavirus-killer-spanish-flu-killed-five-times-more-people-world-war-i-130757.

[vii] Carol R. Byerly, “Institutional Response: The U.S. Military and the Influenza Pandemic of 1918–1919,” Public Health Reports - Supplement 125, no. 3 (2010): 87.

[viii] Christopher Watterson and Adam Kamradt-Scott, “Fighting Flu: Securitization and the Military Role in Combating Influenza,” Armed Forces & Society 42, no. 1 (January 2016): 150-151.

[ix] Olivier Lahaie, “L’épidémie de grippe dite ‘espagnole’ et sa perception par l’armée française (1918-1919)” Revue historique des armées 262 (2011): 6.

[x] Jörg Vögele, “Die ‘Spanische Grippe’ in der deutschen Armee 1918: Perspektive der Arzte und Generäle,”

Medizin Historisches Journal 48, no. 2 (January 2013): 123.

[xi] Michael Bresalier, “Fighting Flu: Military Pathology, Vaccines, and the Conflicted Identity of the 1918–19 Pandemic in Britain,” Journal of the History of Medicine 68, no. 1 (January 2013): 89-90; and Christopher Watterson and Adam Kamradt-Scott, “Fighting Flu: Securitization and the Military Role in Combating Influenza,” Armed Forces & Society 42, no. 1 (January 2016): 151.

[xii] Mark Humphries, “The Horror at Home: The Canadian Military and the ‘Great’ Influenza Pandemic of 1918.” Journal of the Canadian Historical Association / Revue de la Société historique du Canada 16, no. 1 (2005): 255-256.

[xiii] Pierre Darmon, “Une tragédie dans la tragédie : la grippe espagnole en France (avril 1918-avril 1919),” Annales

de démographie historique 2 (2000), 162; and see Captain Thomas L. Snyder, “Navy Support to Civilian Authorities during the 1918 Influenza Pandemic-History’s Lessons and Recommendations for Future Work,” Military Medicine 174 (November 2009): 1223-1227.

[xiv] Canada, Global Affairs Canada, Emails, “ROME SITREP COVID-19 (Coronavirus) Outbreak #1 - #34” (11 March - 14 April 2020). In possession of Author.

[xv] See United States, Department of Defense, “DoD COVID-19 UPDATE April 13, 2020,” accessed 16 April 2020, https://www.govexec.com/media/gbc/docs/pdfs_edit/covid-19_media_fact_sheet_-_13_apr_20.pdf; and Foreign Policy, e-mail message to author, 16 April 2020.

Published: Mar 14, 2022