By: HISTORY.com Editors

Spanish Flu

Spanish Flu Virus
BSIP/UIG/Getty Images
Published: October 12, 2010Last Updated: May 28, 2025

The Spanish flu pandemic of 1918-1919 was the deadliest pandemic in world history, infecting some 500 million people across the globe—roughly one-third of the population—and causing up to 50 million deaths, including some 675,000 deaths in the United States alone. The disease, caused by a new variant of the influenza virus, was spread in part by troop movements during World War I. Though the flu pandemic hit much of Europe during the war, news reports from Spain weren’t subject to wartime censorship, so the misnomer “Spanish flu” entered common usage. With no vaccines or effective treatments, the pandemic caused massive social disruption: Schools, theaters, churches and businesses were forced to close, citizens were ordered to wear masks and bodies piled up in makeshift morgues before the virus ended its deadly worldwide march in early 1920.

What Is the Flu?

Influenza, or flu, is a virus that attacks the respiratory system. The flu virus is highly contagious: When an infected person coughs, sneezes or talks, respiratory droplets are generated and transmitted into the air, and can then can be inhaled by anyone nearby.

Additionally, a person who touches something with the virus on it and then touches his or her mouth, eyes or nose can become infected.

Did you know?

During the flu pandemic of 1918, the New York City health commissioner tried to slow the transmission of the flu by ordering businesses to open and close on staggered shifts to avoid overcrowding on the subways.

Flu outbreaks happen every year and vary in severity, depending in part on what type of virus is spreading. (Flu viruses can rapidly mutate.)

Flu Season

The Spanish Flu Was Deadlier Than World War I

In 1918 the Spanish Flu killed at least 50 million people around the world and was the second deadliest plague in history–after, well, the plague in the 1300s. But how exactly did a flu virus cause such massive death and destruction across the world?

5:42m watch

In the United States, “flu season” generally runs from late fall into spring. In a typical year, more than 200,000 Americans are hospitalized for flu-related complications, and over the past three decades, there have been some 3,000 to 49,000 flu-related U.S. deaths annually, according to the Centers for Disease Control and Prevention.

Young children, people over age 65, pregnant women and people with certain medical conditions, such as asthma, diabetes or heart disease, face a higher risk of flu-related complications, including pneumonia, ear and sinus infections and bronchitis.

A flu pandemic, such as the one in 1918, occurs when an especially virulent new influenza strain for which there’s little or no immunity appears and spreads quickly from person to person around the globe.

Spanish Flu Symptoms

The first wave of the 1918 pandemic occurred in the spring and was generally mild. The sick, who experienced such typical flu symptoms as chills, fever and fatigue, usually recovered after several days, and the number of reported deaths was low.

However, a second, highly contagious wave of influenza appeared with a vengeance in the fall of that same year. Victims died within hours or days of developing symptoms, their skin turning blue and their lungs filling with fluid that caused them to suffocate. In just one year, 1918, the average life expectancy in America plummeted by a dozen years.

What Caused the Spanish Flu?

It’s unknown exactly where the particular strain of influenza that caused the pandemic came from; however, the 1918 flu was first observed in Europe, America and areas of Asia before spreading to almost every other part of the planet within a matter of months.

Despite the fact that the 1918 flu wasn’t isolated to one place, it became known around the world as the Spanish flu, as Spain was hit hard by the disease and was not subject to the wartime news blackouts that affected other European countries. (Even Spain's king, Alfonso XIII, reportedly contracted the flu.)

One unusual aspect of the 1918 flu was that it struck down many previously healthy, young people—a group normally resistant to this type of infectious illness—including a number of World War I servicemen.

In fact, more U.S. soldiers died from the 1918 flu than were killed in battle during the war. Forty percent of the U.S. Navy was hit with the flu, while 36 percent of the Army became ill, and troops moving around the world in crowded ships and trains helped to spread the killer virus.

Although the death toll attributed to the Spanish flu is often estimated at 20 million to 50 million victims worldwide, other estimates run as high as 100 million victims—around 3 percent of the world’s population. The exact numbers are impossible to know due to a lack of medical record-keeping in many places.

What is known, however, is that few locations were immune to the 1918 flu—in America, victims ranged from residents of major cities to those of remote Alaskan communities. Even President Woodrow Wilson reportedly contracted the flu in early 1919 while negotiating the Treaty of Versailles, which ended World War I.

Why Was The Spanish Flu Called The Spanish Flu?

The Spanish Flu did not originate in Spain, though news coverage of it did. During World War I, Spain was a neutral country with free media that covered the outbreak from the start, first reporting on it in Madrid in late May of 1918. Meanwhile, Allied countries and the Central Powers had wartime censors who covered up news of the flu to keep morale high. Because Spanish news sources were the only ones reporting on the flu, many believed it originated there (the Spanish, meanwhile, believed the virus came from France and called it the “French Flu.”)

Where Did The Spanish Flu Come From?

Boys wear bags of camphor around their necks around the time of the 1918-19 Spanish flu—an “old-wives’ method of flue-prevention,” according to a December 1946 issue of Life magazine.

Bettmann Archive/Getty Images

The Spanish flu was a huge concern for WWI military forces. Here, men gargle saltwater to prevent infection at the War Garden at Camp Dix (now Fort Dix) in New Jersey, circa 1918.Read more: Why October 1918 Was America’s Deadliest Month Ever

PhotoQuest/Getty Images

A woman wears a sci-fi-looking flu nozzle attached to a machine circa 1919. It’s not clear how it worked or if it had any health benefits.

Topical Press Agency/Getty Images

Donning a mask, a man uses a pump to spray an unknown “anti-flu” substance in the United Kingdom, circa 1920.

Hulton-Deutsch Collection/Corbis/Getty Images

Professor Bordier of France’s University of Lyon apparently claimed that this machine could cure colds in minutes. This photo circa 1928 shows him demonstrating his own machine.

Bettmann Archive/Getty Images

People in London wear masks to avoid catching the flu circa 1932. This is a preventative method people still use around the world today.

Fox Photos/Getty Images

People in England wear different-looking masks to prevent the flu circa 1932.

Imagno/Getty Images

This baby’s parents had the right idea in this photo circa 1939. The flu can spread between people up to six feet away, and because babies have a high risk of developing serious flu-related complications, it’s best for people who haven’t received flu shots to stay away.Read more: Pandemics That Changed History

Harry Shepherd/Fox Photos/Getty Images

British actress Molly Lamont (far right) receives her “emergency flu rations” of oranges at Elstree Studios in London, circa 1940.

Fox Photos/Getty Images

Scientists still do not know for sure where the Spanish Flu originated, though theories point to France, China, Britain, or the United States, where the first known case was reported at Camp Funston in Fort Riley, Kansas, on March 11, 1918.

Some believe infected soldiers spread the disease to other military camps across the country, then brought it overseas. In March 1918, 84,000 American soldiers headed across the Atlantic and were followed by 118,000 more the following month.

Fighting the Spanish Flu

When the 1918 flu hit, doctors and scientists were unsure what caused it or how to treat it. Unlike today, there were no effective vaccines or antivirals, drugs that treat the flu. (The first licensed flu vaccine appeared in America in the 1940s. By the following decade, vaccine manufacturers could routinely produce vaccines that would help control and prevent future pandemics.)

Complicating matters was the fact that World War I had left parts of America with a shortage of physicians and other health workers. And of the available medical personnel in the U.S., many came down with the flu themselves.

Additionally, hospitals in some areas were so overloaded with flu patients that schools, private homes and other buildings had to be converted into makeshift hospitals, some of which were staffed by medical students.

Officials in some communities imposed quarantines, ordered citizens to wear masks and shut down public places, including schools, churches and theaters. People were advised to avoid shaking hands and to stay indoors, libraries put a halt on lending books and regulations were passed banning spitting.

According to The New York Times, during the pandemic, Boy Scouts in New York City approached people they’d seen spitting on the street and gave them cards that read: “You are in violation of the Sanitary Code.”

Aspirin Poisoning and the Flu

Leprosy

Leprosy, a slow bacterial disease causing sores and deformities, became a medieval European pandemic seen as God’s punishment in families.

De Agostini/Getty Images
Black Death

The Black Death, a bubonic plague pandemic, spread rapidly and decimated Earth’s population, earning its name in the 17th century.

Bettmann Archive/Getty Images
The Great Plague of 1665 to 1666 graph

The bubonic plague killed 20% of London’s population, ending in 1666 as the Great Fire struck, devastating the city further.

Hulton Archive/Getty Images
Cholera epidemic

The first of seven cholera pandemics began in Russia, killing a million, then spread via soldiers to India, killing millions more.

Photo 12/Universal Images Group/Getty Images

The 1889 flu began in Siberia, spread through Europe via Moscow and Poland, and by year’s end had killed 360,000 people.

National Library of Medicine
Spanish Flu, 1918

The 1918 avian flu began in Europe, the U.S., and Asia, killing 50 million worldwide with no drugs or vaccines to stop it.

Universal History Archive/Universal Images Group/Getty Images

The 1957 Asian flu began in Hong Kong, spread worldwide, and killed 1.1 million globally, including 116,000 in the U.S.

Ed Clark/The LIFE Picture Collection/Getty Images
HIV/AIDS Epidemic

Identified in 1981, AIDS weakens the immune system. Originating from a 1920s chimpanzee virus, it has killed 35 million people.

Acey Harper/The LIFE Images Collection/Getty Images
SARS Virus, 2003

Identified in 2003, SARS likely began with bats, spread to cats, then humans, infecting 8,096 people and killing 774 worldwide.

Peter Parks/AFP/Getty Images
COVID-19, Coronavirus

COVID-19, a novel coronavirus, emerged in China in 2019 and spread to 163 countries, killing nearly 24,000 by March 2020.

STR/AFP/Getty Images

With no cure for the flu, many doctors prescribed medication that they felt would alleviate symptoms… including aspirin, which had been trademarked by Bayer in 1899—a patent that expired in 1917, meaning new companies were able to produce the drug during the Spanish Flu epidemic.

Before the spike in deaths attributed to the Spanish Flu in 1918, the U.S. Surgeon General, Navy and the Journal of the American Medical Association had all recommended the use of aspirin. Medical professionals advised patients to take up to 30 grams per day, a dose now known to be toxic. (For comparison’s sake, the medical consensus today is that doses above four grams are unsafe.) Symptoms of aspirin poisoning include hyperventilation and pulmonary edema, or the buildup of fluid in the lungs, and it’s now believed that many of the October deaths were actually caused or hastened by aspirin poisoning.

The Flu Takes Heavy Toll on Society

The flu took a heavy human toll, wiping out entire families and leaving countless widows and orphans in its wake. Funeral parlors were overwhelmed and bodies piled up. Many people had to dig graves for their own family members.

The flu was also detrimental to the economy. In the United States, businesses were forced to shut down because so many employees were sick. Basic services such as mail delivery and garbage collection were hindered due to flu-stricken workers.

In some places there weren’t enough farm workers to harvest crops. Even state and local health departments closed for business, hampering efforts to chronicle the spread of the 1918 flu and provide the public with answers about it.

How U.S. Cities Tried to Stop The 1918 Flu Pandemic

A devastating second wave of the Spanish Flu hit American shores in the summer of 1918, as returning soldiers infected with the disease spread it to the general population—especially in densely-crowded cities. Without a vaccine or approved treatment plan, it fell to local mayors and healthy officials to improvise plans to safeguard the safety of their citizens. With pressure to appear patriotic during wartime and with a censored media downplaying the disease’s spread, many made tragic decisions.

Philadelphia’s response was too little, too late. Dr. Wilmer Krusen, director of Public Health and Charities for the city, insisted mounting fatalities were not the “Spanish flu,” but rather just the normal flu. So on September 28, the city went forward with a Liberty Loan parade attended by tens of thousands of Philadelphians, spreading the disease like wildfire. In just 10 days, over 1,000 Philadelphians were dead, with another 200,000 sick. Only then did the city close saloons and theaters. By March 1919, over 15,000 citizens of Philadelphia had lost their lives.

St. Louis, Missouri, was different: Schools and movie theaters closed and public gatherings were banned. Consequently, the peak mortality rate in St. Louis was just one-eighth of Philadelphia’s death rate during the peak of the pandemic.

Citizens in San Francisco were fined $5—a significant sum at the time—if they were caught in public without masks and charged with disturbing the peace.

Spanish Flu Pandemic Ends

By the summer of 1919, the flu pandemic came to an end, as those that were infected either died or developed immunity.

Almost 90 years later, in 2008, researchers announced they’d discovered what made the 1918 flu so deadly: A group of three genes enabled the virus to weaken a victim’s bronchial tubes and lungs and clear the way for bacterial pneumonia.

Since 1918, there have been several other influenza pandemics, although none as deadly. A flu pandemic from 1957 to 1958 killed around 2 million people worldwide, including some 70,000 people in the United States, and a pandemic from 1968 to 1969 killed approximately 1 million people, including some 34,000 Americans.

More than 12,000 Americans perished during the H1N1 (or “swine flu”) pandemic that occurred from 2009 to 2010. The COVID-19 pandemic, which started in December 2019, spread around the world before an effective COVID-19 vaccine was made available in December 2020. By May of 2023, when the World Health Organization declared an end to the global coronavirus emergency, almost 7 million people had died of COVID-19.

Each of these modern day pandemics brings renewed interest in and attention to the Spanish Flu, or “forgotten pandemic,” so-named because its spread was overshadowed by the deadliness of World War I and covered up by news blackouts and poor record-keeping.

Sources

Salicylates and Pandemic Influenza Mortality, 1918–1919 Pharmacology, Pathology, and Historic Evidence. Clinical Infectious Diseases.

In 1918 Pandemic, Another Possible Killer: Aspirin. The New York Times.

How the Horrific 1918 Flu Spread Across America. Smithsonian Magazine.

What the Spanish Flu Debacle Can Teach Us About Coronavirus. Politico.

WHO declares end to Covid global health emergency. NBC News.

COVID-19 Dashboard. WHO.

Related Articles

A Pennsylvania construction worker has discovered a mass grave thought to contain victims of the 1918 flu pandemic.

How do populations survive a pandemic? History offers some strategies.

Vaccines are so effective at fighting disease that sometimes it’s easy to forget their impact.

After millions perished, people turned to séances, Ouija boards and more to help communicate with their dearly departed.

About the author

HISTORY.com Editors

HISTORY.com works with a wide range of writers and editors to create accurate and informative content. All articles are regularly reviewed and updated by the HISTORY.com team. Articles with the “HISTORY.com Editors” byline have been written or edited by the HISTORY.com editors, including Amanda Onion, Missy Sullivan, Matt Mullen, Christian Zapata and Cristiana Lombardo.

Fact Check

We strive for accuracy and fairness. But if you see something that doesn't look right, click here to contact us! HISTORY reviews and updates its content regularly to ensure it is complete and accurate.

Citation Information

Article title
Spanish Flu
Website Name
History
Date Accessed
October 10, 2025
Publisher
A&E Television Networks
Last Updated
May 28, 2025
Original Published Date
October 12, 2010

History Revealed

Sign up for Inside History

Get fascinating history stories twice a week that connect the past with today’s world, plus an in-depth exploration every Friday.

By submitting your information, you agree to receive emails from HISTORY and A+E Global Media. You can opt out at any time. You must be 16 years or older and a resident of the United States.More details: Privacy Policy | Terms of Use | Contact Us
King Tut's gold mask
Advertisement
Advertisement
Advertisement