Men wearing white cloth masks lay on wooden cots under wool blankets.

Revealing Data: Flu Masks on Ships, 1918

Circulating Now welcomes guest bloggers Ariel Ludwig, Jessica Brabble, and E. Thomas Ewing, from Virginia Tech to explore the use of masks on World War I transport ships for prevention of influenza.

On October 31, 1918, at the height of the influenza epidemic, newspapers across the United States began to report that a ship carrying six thousand soldiers reached Europe with only fifty cases and one death from this disease. Most newspapers reprinted the simple explanation from a wire service report: “The success achieved in combating the malady was due, in the opinion of physicians, to the fact that every man wore a cloth mask during the voyage.” Headlines emphasized the success of this measure: “Masks Balk Influenza on Transport Ship” (Pensacola Journal); “Men Wore Masks Escape Disease” (Republican Farmer); “Flu Masks Worked” (Atchison Daily Globe); “All Wore Cloth Masks” (Alexandria Gazette), and “Yanks on Ship Escape Grip by Using Masks (Detroit Free Press).

The widespread reports on this particular voyage marked an important convergence of two critical processes in fall 1918: the urgency of the American war effort, which depended upon transporting as many men as possible across the Atlantic to fight against the Germans, and the influenza epidemic, which reached the United States in late August and spread rapidly across the country, resulting in more than 650,000 deaths in the six months that followed. According to The Medical Department of the United States Army in the World War (Vol. 9), the United States military forces counted 44,370 deaths from influenza, pneumonia, or related diseases, during the first world war, a total nearly as great as the 50,385 battle deaths (p. 68).

Thousands of men packed on a transport ship brought the imperative to build up military forces in Europe into direct conflict with the challenge of reinforcing the front lines as more soldiers were wounded and killed in action. In the words of historian Carol Byerly, “Influenza sailed with American troops across the Atlantic.” By September 1918, 250,000 men a month were being transported across the Atlantic to reinforce the front lines. Claims that “flu masks worked” thus appeared both to support the war effort and justify similar measures implemented by health departments seeking to control local outbreaks. While most newspapers reprinted the same brief statements about victims and masks, a few newspapers, including the Brattleboro Daily Reformer, included an additional sentence providing important context: “There were several fatalities on the same ship during her previous voyage and the army and navy officials here were face to face with what threatened to be a serious situation.”

This reference to “a serious situation” marks an unusually public acknowledgement that the epidemic posed a direct threat to the American war effort. In late September and October, transport ships departed the United States with thousands of men on board—and many reached British and French ports with hundreds of men infected and dozens dead. The USS Wilhelmina departed on September 23, and arrived in France with nearly 500 infected soldiers and 14 deaths. The USS Leviathan departed a week later, with more than 11,000 on board, and arrived in France with more than 2,000 infected soldiers and sailors. Seventy men died at sea, fourteen more died in the port, and hundreds died after they were admitted to influenza wards in France. The cost in human lives as well as the detrimental impact on the war effort thus motivated the medical corps to find ways to control the spread of infectious disease.

Men wearing white cloth masks lay on wooden cots under wool blankets in a bare room.
U.S. Army Field Hospital No. 29, Hollerich, Luxembourg: Influenza Ward, ca 1918
National Library of Medicine #101400304
Two men in shorts and gloves box on the deck of a ship watched by a dense crowd most of whom wear cloth masks.
USS Siboney, ca. 1918
Courtesy Naval History and Heritage Command #103264

The use of masks on ships thus appeared as a relatively simple measure that achieved significant outcomes. A photograph of soldiers cheering a boxing match while (mostly) wearing masks on the USS Siboney suggests how this measure was adapted into the normal routine of transporting troops. A closer look at contemporary reports indicates, however, that masks worked in combination with other health measures. According to General Peyton March, who spoke to newspaper reporters on November 2, significant decreases in influenza cases on transports resulted from fewer troops on each ship, improved medical services, and “men are wearing masks across.” The British Medical Journal, in a November 9 editorial, attributed to the decrease in cases “a careful medical examination of all men before they are admitted on to the transport,” “the universal use of a face mask,” and any men falling ill on the transport are “immediately isolated.”

While the toll of lives lost on transport ships and measures to mitigate the epidemic were only partially reported in newspapers, the full scope of measures were described in detail in reports published after the war. As described in the Annual Report of the Surgeon General, U.S. Army (1919), soldiers were checked by physicians when they arrived at embarkation points. Any soldiers showing symptoms of influenza were removed from their unit to a detention center—along with those in contact with the sick. Prior to boarding, physicians carefully observed the troops and again removed any showing signs of illness. These monitoring and isolating measures probably meant that relatively few infected men were boarding the troop ships at the start of the voyage. The effectiveness of masks was thus enhanced by measures that identified those infected, removed them from the rest of the population, and isolated their close contacts.

A page from a book showing a chart of annual admission rates per 1000 from June to December 1918 peaking in early October.
The Medical Incidence of Influenza and Influenzal Pneumonia, by weeks for certain camps in the United States June 17 to December 29, 1918 in Department of the United States Army in the World War (Vol. 9), 1929
National Library of Medicine #14120390RX9

Timing also contributed to the relative success of this particular transport ship. A chart published in The Medical Department of the United States Army in the World War (Vol. 9) shows the remarkable eight week surge in hospital admissions that began in late August. By the third week of October, when this transport ship presumably left the United States with 6,000 men wearing masks, the number of infected men had begun to decrease. More granular data for Newport News, Virginia, one of the most important embarkation ports, also published in The Medical Department of the United States Army in the World War (Vol. 5) illustrates a similar trend. The daily infection rate for influenza rose dramatically in late September and early October, with a seven-day average more than fifty times greater than prior to the epidemic. These rates diminished considerably by the third week of October. Hospital admissions and morbidity statistics are particularly useful for measuring the scope and impact of an epidemic, as they illustrate the number of cases within a defined population.

A bar chart showing daily morbidity rate per 1000 by week from september 8 to November 10, peaking at 12 on October 6 and under 1 on October 27.
Infection rate for influenza in Newport News, Virginia
Based on Data in The Medical Department of the United States Army in the World War (Vol. 5), 1928

Did men on ships actually wear masks? Our research on flu masks in 1918 has sought to answer this question using reports of arrests, debates in local government, and photographic evidence from Armistice Day celebrations. The photograph from the USS Siboney shows many men with face masks watching the boxing match, but a significant number either with no mask or with their masks around their necks. Of course, the soldiers were outside, where the likelihood of infection was decreased by more rapid air circulation. We can gauge the likelihood of mask wearing by another photograph of men on a troop transport ship published in American newspapers in early November. In this photograph, under the headline, “Scene on a Transport Loaded with Americans,” none of the men wear masks. The photograph’s caption makes no mention of the influenza epidemic: “American troops on a transport on their way to France to take part in the great struggle now raging. Each man constantly carries his life preserver and is always ready for any emergency.” The juxtaposition of an article crediting masks for saving lives and a photograph with no evidence of mask wearing illustrate the inconsistency of mask requirements even in the controlled environment of a military transport ship.

A newspaper photo of the deck of a ship crowded with men in uniform at leisure.
“Scene on a Transport Loaded with Americans” in The Meridian Times, November 01, 1918
Courtesy Library of Congress, Chronicling America

On November 11, the Armistice ended the war, thus eliminating the urgency of transporting men across the Atlantic. The most durable legacy of this moment in history is the recognition of Veterans Day, which began with the official commemoration of Armistice Day, by President Wilson on the first anniversary. In 1954, President Eisenhower signed legislation designating Veterans Day as holiday for all military veterans. As we commemorate Veterans Day 2020, it is important to remember the devastating effect a global pandemic had on the soldiers and sailors of the First World War and how it shaped the context in which the war ended.

A young woman in glasses.Ariel Ludwig recently received her doctoral degree in Science and Technology in Society (STS) from Virginia Tech. Her research addresses the intersection of medicine, public health, and the criminal justice system.


An informal portrait of a young woman outdoors.Jessica Brabble is a second-year graduate student in history at Virginia Tech , with research interests in disability history, the history of popular culture, and entertainment history.


Portrait of Tom Ewing outside.E. Thomas Ewing is a professor of history at Virginia Tech, with research interests in the history of influenza epidemics. In 2018, he directed a summer workshop on the 1918 influenza epidemic funded by the National Endowment for the Humanities in partnership with the History of Medicine Division, National Library of Medicine. @ethomasewing

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