The Great Influenza Summary

The great 1918 influenza pandemic remains a reminder of how nature's smallest organisms can upend human societies. Why was this outbreak so deadly, and how did the world respond?

1. American Medicine Was Transforming but Unprepared

In the late 19th century, American medicine was behind Europe, with medical schools operating as profit-driven institutions. By 1900, however, institutions like Johns Hopkins and the Rockefeller Institute raised standards. These centers recruited the best minds, including renowned researchers like William Welch. America approached World War I as an emerging leader in medical advancements.

Yet even with the improvements, old inefficiencies lingered. American universities had been enrolling students without strict measures of talent, with some schools granting medical degrees despite students' poor performance. These gaps became evident when faced with the influenza pandemic. Many of the world’s brightest scientists were converging in these institutes, but even world-class academia couldn’t prepare for an invisible, fast-evolving enemy like the flu.

The opening of Welch’s School of Public Health in 1918 symbolized America’s growing determination to combat diseases. Ironically, Welch himself fell ill during the pandemic’s peak. Though the country had a burgeoning group of talented researchers, their work couldn’t keep pace with the rapid and unprecedented spread of infection.

Examples

• Harvard granted medical degrees in the 1870s despite students failing more than half their courses.
• Johns Hopkins introduced rigorous standards and modernized medical education in America.
• William Welch, founder of public health at Hopkins, was sidelined early in the pandemic by the flu itself.

2. The Influenza Virus Is a Master of Mutation

The influenza virus is highly adaptive, changing constantly to evade the immune system. The 1918 strain was particularly dangerous because it underwent mutations that made it uniquely deadly for humans. Viruses replicate by infecting host cells and rewriting the cells’ genetic instructions, creating a cascade of new virus particles.

Unlike DNA, RNA (the genetic material used by influenza) lacks error-checking during replication, which leads to frequent mutations. Viruses like influenza exploit these “mistakes” to evolve rapidly, finding better ways to infect new hosts. Originating from aquatic birds, the 1918 virus jumped to swine, eventually making its way into humans. This adaptability allowed it to spread quickly and broadly.

The flu’s mutability is a primary reason why pandemics remain such a threat. The 1918 strain was novel to humans, which meant immune systems had no pre-existing defense against it. Thus, it overwhelmed its victims' bodies, leading to skyrocketing infection rates and mass casualties.

Examples

• A single influenza molecule can create up to a million new virus proteins during replication.
• The 1918 strain likely made a species jump from birds to humans through pigs.
• The virus outwitted immune systems by evolving faster than defenses could adapt.

3. World War I Set the Stage for the Pandemic

As the United States mobilized for war, millions of soldiers and city workers gathered in crowded conditions ideal for spreading the virus. Vast military encampments housed men with varying immunities, sharing germs in barracks and mess halls. Packed urban homes, driven by wartime migration for factory jobs, further exacerbated transmission.

Military movements amplified the outbreak. Troops who trained in American camps carried the virus abroad, while sick soldiers who’d returned home spread it further. Public health officials acknowledged the risk but prioritized troop deployment over containment efforts. This decision inadvertently sent the flu worldwide, devastating civilian populations.

Cities were overwhelmed. Healthcare infrastructure, stretched thin by the war, was unprepared for mass illness. Overflowing hospitals forced many to recover—or die—in cramped apartments, endangering families and neighbors. The war effort inadvertently became a catalyst for global suffering and death.

Examples

• 56,000 men at Camp Funston in Kansas were an initial outbreak hub.
• Urban housing shortages caused several families to share overcrowded apartments.
• Troops leaving the US spread the virus to Europe and beyond.

4. The Virus’s Second Wave Was Deadlier

In spring 1918, the influenza’s first wave seemed mild, resembling a typical flu. Yet as the virus spread across the globe, it mutated and became far deadlier by the fall of the same year. This second wave caused widespread fatalities and was marked by horrifying symptoms, including cyanosis, where skin turned blue or black from lack of oxygen.

Military and civilian leaders underestimated this new wave’s potential. At Camp Devens near Boston, hospitals designed for 1,200 patients saw 6,000 flu admissions at once. Cities like Philadelphia allowed massive gatherings to continue, worsening the outbreak. Victims endured rapid-onset symptoms, sometimes dying within hours of initial fever.

This wave’s lethality is often attributed to its ability to exploit healthy immune systems. Young, fit adults were paradoxically at the highest risk of death. Their robust immune responses flooded lungs with fluid in a failed attempt to neutralize the virus, suffocating them instead.

Examples

• Camp Devens physicians described patients turning “blue-black” before dying.
• Philadelphia's parade on September 28 brought 200,000 people together, worsening infections.
• The second wave targeted young adults more than the elderly or infants.

5. Chaos and Denial Worsened the Crisis

In cities like Philadelphia, government leaders downplayed or denied the pandemic’s severity. Despite clear warnings, officials permitted events like parades, where massive crowds unknowingly spread the virus. Overcrowded hospitals lacked staff, beds, or supplies to treat the growing numbers of critically ill patients.

Panic set in as bodies piled up in morgues, overflowing into makeshift storages. Families could no longer bury their loved ones, and wagons patrolled streets to collect the dead. Yet many leaders prioritized calm and war objectives over confessing the bleak reality. The lack of transparency deepened public mistrust and hindered containment efforts.

Military leaders made similarly disastrous choices. They continued deploying soldiers despite warnings from medical experts. These ill-advised decisions ensured that both the virus and misinformation spread far more widely than they otherwise might have.

Examples

• Philadelphia's lack of hospital beds left thousands untreated.
• Over 4,500 Philadelphians died in a single week in October 1918.
• Troops infected aboard naval ships perpetuated outbreaks globally.

6. The Young and Healthy Were Hit Hardest

While flu typically targets the very old and very young, the 1918 strain uniquely killed those in their 20s and 30s. Pregnant women were particularly vulnerable, with staggering mortality rates. Healthy immune systems overreacted to the virus, causing destructive inflammation.

The rapid course of the illness left little time for intervention. Some victims died within 12 hours, while others suffocated as debris from their immune response filled their lungs. Reports of agony and hallucinations painted a grim picture of these young lives cut short.

This unusual trend made the pandemic’s social impact even more devastating. Entire families lost their breadwinners, and orphaned children flooded orphanages. Generations bore the scars of losing able-bodied adults to a flu that weaponized the human body's defenses against itself.

Examples

• Subcutaneous emphysema, or air bubbles under the skin, was common in fatal cases.
• Mortality among pregnant women approached 70 percent.
• In some areas, nearly 22 percent of populations were wiped out, including Western Samoa.

7. Scientists Faced More Questions Than Answers

Despite advances, scientists struggled to pinpoint the pathogen causing the 1918 flu. Initial theories blamed a bacterium, Bacillus influenzae, but inconclusive studies cast doubt on this idea. The inability to isolate the exact agent delayed vaccine development and limited effective treatments.

Oswald Avery at Rockefeller Institute led extensive investigations but couldn’t confirm B. influenzae as the culprit. A competing team at the New York City Department of Public Health similarly reversed their claims about the bacterium, leaving researchers grappling with uncertainty. Ultimately, the virus itself wouldn’t be identified until 1933.

Science raced against nature’s clock, but a lack of tools, understanding, and coordinated research hampered progress. By the time answers emerged, the pandemic had already subsided, with over 100 million lives lost worldwide.

Examples

• Researchers failed to identify the influenza virus in 1918 and relied on guesswork.
• Vaccine attempts based on bacterial theories proved ineffective.
• The virus was only conclusively identified decades later, in 1933.

8. Government Inaction Magnified Global Deaths

Government responses—or the lack thereof—played a tragic role. President Wilson never publicly acknowledged the outbreak, choosing to focus entirely on the war effort. Orders for troop movements and exports continued, turning soldiers and cargo ships into vectors for further disease spread.

The US medical infrastructure was crippled in key areas. Wilson’s administration diverted doctors and nurses to military service, leaving civilian hospitals understaffed. Even when death rates soared in cities, there were few interventions to protect the public.

Globally, American decisions had consequences. Millions of troops and supplies sent overseas spread the pandemic into countries already weakened by war. In more isolated regions, where populations lacked flu exposure, the mortality rate surged even higher.

Examples

• American troop ships infected European and worldwide ports after arriving from the US.
• Civilian hospitals lost staff to mandatory military service.
• Wilson's refusal to discuss the flu perpetuated a lack of coordinated action.

9. The Legacy of the Pandemic Erupts in Unseen Ways

The immediate effects of the pandemic were profound, but the long-term consequences were equally startling. Neurological damage from the infection left some survivors physically and mentally impaired. President Wilson, who contracted the flu, showed lasting changes, with worsening paranoia that may have influenced his lenient stance toward France’s demands in the Treaty of Versailles.

The societal toll included millions of orphans and lasting memories of suffering. Not addressed for decades after, public health infrastructure eventually started emphasizing pandemic preparedness in response to the sheer horror of 1918.

The psychological imprint of the pandemic, compounded by World War I’s devastation, shaped a generation. These ripples extended into global political decisions, economic instability, and even the environmental consequences of human population loss.

Examples

• Wilson’s post-flu paranoia shaped the harsh terms of the Treaty of Versailles.
• Over 21,000 New York children became orphans in 1918.
• Modern pandemic planning often looks back to the failures of 1918 as a warning.

Takeaways

1. Strengthen public communication during health crises to avoid misinformation and encourage compliance with safety measures.
2. Invest in viral research focused on mutation and transmission to stay ahead of future pandemics.
3. Build robust, flexible public health infrastructure that balances resources across military and civilian sectors during crises.