The 1918 Spanish Flu spread in distinct waves: it emerged in March 1918 at Camp Funston, Kansas, then surged through troop travel to major U.S. cities by May. A second wave began in August 1918 in Brest, France, and by September it had reached India via Bombay. The virus was H1N1 influenza A, and the most devastating outcomes came when secondary bacterial pneumonia followed infection.
Key Takeaways
- The pandemic first emerged in March 1918 at Camp Funston, Kansas, with rapid spread among troops.
- By May 1918, the flu had reached major U.S. cities like New York, Chicago, and Philadelphia via troop movements.
- The second wave began in August 1918 in Brest, France, spreading via returning U.S. soldiers to Europe.
- The virus strain was an H1N1 influenza A, sequenced from preserved 1918 lung tissues.
- The 1918 flu uniquely caused high mortality in healthy young adults aged 20-40 due to cytokine storm.
- Most deaths resulted from secondary bacterial pneumonia, with pathogens like Streptococcus pneumoniae.
- The 1918 influenza pandemic, also known as the Spanish Flu, is estimated to have killed between 50 million and 100 million people worldwide, making it one of the deadliest pandemics in history.
- In the United States alone, the Spanish Flu caused approximately 675,000 deaths between September 1918 and April 1919.
- Globally, the pandemic infected about one-third of the world's population, roughly 500 million people, out of a total population of around 1.8 billion.
- U.S. implemented mask mandates in 25 states, with fines up to $100.
- St. Louis closed schools, churches, and theaters early, reducing deaths per capita by 50% vs. Philadelphia.
- U.S. Public Health Service distributed gauze masks to 8 million people.
- The pandemic caused schools, theaters, and churches to close across U.S. cities, halting public gatherings.
- U.S. economy lost $13 billion (1918 dollars) due to workforce absences and deaths.
- Orphanages overflowed; in New York City, 2,000 children lost both parents.
The 1918 H1N1 Spanish flu spread in deadly waves worldwide, infecting about one third and killing 50 to 100 million.
Related reading
01 · Category
Geographical Spread19 stats
01
The pandemic first emerged in March 1918 at Camp Funston, Kansas, with rapid spread among troops.
02
By May 1918, the flu had reached major U.S. cities like New York, Chicago, and Philadelphia via troop movements.
03
The second wave began in August 1918 in Brest, France, spreading via returning U.S. soldiers to Europe.
04
In September 1918, the flu arrived in India via Bombay, spreading inland and causing massive outbreaks.
05
Spain reported widespread cases in May 1918 despite neutrality in WWI, leading to the "Spanish Flu" name due to uncensored press.
06
By October 1918, the pandemic had reached every continent except Antarctica, infecting remote Pacific islands.
07
In Africa, the flu entered via Cape Town in September 1918, spreading northward through rail and trade routes.
08
Australia delayed arrival until January 1919 through naval quarantine, but eventual spread affected all states.
09
In China, the flu spread from Hong Kong in mid-1918, affecting northern provinces severely by winter.
10
Siberia saw outbreaks in Vladivostok in October 1918, spreading via Trans-Siberian Railway.
11
Brazil's first cases appeared in Recife in September 1918, rapidly moving to Rio de Janeiro.
12
In Japan, the flu arrived via U.S. naval ships in September 1918, peaking in military bases.
13
Iran's outbreak started in Tehran in November 1918, facilitated by refugee movements from Russia.
14
In New Zealand, the flu bypassed quarantine on the SS Talune, arriving in Auckland on November 12, 1918.
15
Samoa's catastrophic outbreak began after the SS Talolo arrived on November 7, 1918, without quarantine.
16
In Peru, the flu entered via Callao port in August 1918, spreading to Lima and highlands.
17
Canada's first wave hit in fall 1918, with Quebec and Ontario seeing peak hospitalizations.
18
In the UK, the flu peaked in waves from July to December 1918, affecting London hardest.
19
Philadelphia's Liberty Loan Parade on September 28, 1918, accelerated local spread, leading to 47,000 cases in days.
Interpretation
Geographical Spread Interpretation
In the geographical spread of the Spanish flu, outbreaks surged across continents within months as it moved from Camp Funston in March 1918 to major US cities by May, reached Europe by August, arrived in India in September, and by October had touched every continent except Antarctica.
02 · Category
Medical Characteristics21 stats
01
The virus strain was an H1N1 influenza A, sequenced from preserved 1918 lung tissues.
02
The 1918 flu uniquely caused high mortality in healthy young adults aged 20-40 due to cytokine storm.
03
Most deaths resulted from secondary bacterial pneumonia, with pathogens like Streptococcus pneumoniae.
04
The virus showed three waves: mild spring 1918, deadly fall 1918, and weaker winter 1919.
05
Incubation period averaged 2 days, with rapid onset of fever, chills, and prostration.
06
Patients often turned cyanotic (blue from oxygen lack) within hours, termed "heliotrope cyanosis."
07
Aspirin overdoses contributed to deaths, with dosages up to 31 grams/day recommended erroneously.
08
The virus hemagglutinin protein had unique mutations enabling lung cell binding and inflammation.
09
No vaccines existed; treatments included quinine, strychnine, and bloodletting unsuccessfully.
10
Autopsies showed "wet" lungs filled with fluid, unlike dry pneumonia in bacterial cases.
11
The virus replicated efficiently in bronchial tissues, unlike seasonal flu in upper airways.
12
Pregnant women had 25-30% mortality if infected, often from pneumonia.
13
Children under 5 had lower mortality than young adults but higher than elderly.
14
Full genomic sequence reconstructed in 2005 from Alaskan permafrost victim.
15
Virus induced hypercytokinemia, with high TNF-alpha and IL-6 levels in animal models.
16
Average duration of illness was 3-5 days for survivors, but fatal cases progressed in 24-48 hours.
17
Blebs and hemorrhages in lungs observed in 1918 autopsies, confirmed by modern reconstructions.
18
The pandemic strain had avian-like polymerase genes, enhancing mammalian transmission.
19
Symptoms included severe headache, eye pain, joint aches, and bleeding from nose/mouth.
20
Survivors often developed bacterial superinfections, treatable today with antibiotics.
21
Mortality peaked in October 1918 globally, with W-shaped age curve unlike U-shaped seasonal flu.
Interpretation
Medical Characteristics Interpretation
Medical characteristics of the 1918 Spanish flu were defined by an H1N1 strain from preserved 1918 lung tissue and a striking clinical pattern of rapid illness with an average 2 day incubation and severe outcomes that struck healthy young adults aged 20 to 40, followed by deaths largely driven by secondary bacterial pneumonia.
03 · Category
Mortality And Death Toll30 stats
01
The 1918 influenza pandemic, also known as the Spanish Flu, is estimated to have killed between 50 million and 100 million people worldwide, making it one of the deadliest pandemics in history.
02
In the United States alone, the Spanish Flu caused approximately 675,000 deaths between September 1918 and April 1919.
03
Globally, the pandemic infected about one-third of the world's population, roughly 500 million people, out of a total population of around 1.8 billion.
04
In India, the Spanish Flu resulted in an estimated 18 million deaths, representing about 5% of the country's population at the time.
05
The death rate for those infected with the 1918 flu was about 2.5%, compared to the typical flu death rate of 0.1%.
06
In the UK, official records indicate 228,000 influenza-related deaths during the pandemic's main wave in late 1918.
07
Among U.S. military personnel, the Spanish Flu killed 43,000 soldiers, more than the number killed in combat during World War I.
08
In France, an estimated 400,000 people died from the flu, with Paris seeing over 50,000 deaths in just two months.
09
The pandemic caused a 20-40% excess mortality rate in young adults aged 20-40 years compared to seasonal influenza.
10
In Samoa, the Spanish Flu wiped out 22% of the population, killing about 8,000 out of 38,000 inhabitants in two months.
11
Total deaths in Brazil from the Spanish Flu were estimated at 300,000, with Rio de Janeiro alone reporting 15,000 deaths.
12
In Australia, despite strict quarantine, 12,000 deaths occurred, representing a mortality rate of 1 in 200 population.
13
Iran's death toll was estimated at 902,400 to 2.4 million, or up to 10% of the population.
14
In South Africa, the flu killed around 300,000 people, with mortality rates reaching 6% in some urban areas.
15
Philadelphia reported 12,191 flu deaths in one week during October 1918, overwhelming morgues and cemeteries.
16
Globally, the case fatality ratio (CFR) for the 1918 pandemic was approximately 2.5%, far higher than modern flu strains.
17
In New Zealand, Māori communities suffered 40-50% mortality rates, compared to 1.4% in European populations.
18
The pandemic led to 50 million deaths worldwide, equivalent to 3-5% of the global population.
19
In Chicago, over 38,000 people died, with daily peaks exceeding 800 deaths in late September 1918.
20
Excess mortality in the U.S. was 799,000, including secondary bacterial pneumonia complications.
21
In Japan, official figures report 390,000 deaths, but estimates suggest up to 23 million cases.
22
Western Samoa (now independent Samoa) had a 20% population loss, one of the highest mortality rates globally.
23
In Peru, coastal regions saw 2-4% mortality, while Andean regions had up to 8-10%.
24
U.S. Navy recorded 24,000 influenza deaths among personnel.
25
In Sweden, 34,000 died, with a mortality rate of 0.46% of the population.
26
Labrador, Canada, saw 70% mortality in some Inuit communities.
27
In the U.S., African Americans had a mortality rate 40% higher than whites in some cities.
28
Global excess deaths estimated at 65 million by some models adjusting for underreporting.
29
In St. Louis, strict measures limited deaths to 748 despite 13,000 cases.
30
Camp Devens, Massachusetts, saw 63 deaths in one day from influenza among 12,000 troops.
Interpretation
Mortality And Death Toll Interpretation
The Spanish flu’s mortality was staggering, with an estimated 50 to 100 million deaths worldwide and in the United States about 675,000 deaths between September 1918 and April 1919, underscoring how this pandemic’s death toll far exceeded typical flu mortality with a 2.5% death rate among the infected.
More related reading
04 · Category
Public Health Response And Legacy25 stats
01
U.S. implemented mask mandates in 25 states, with fines up to $100.
02
St. Louis closed schools, churches, and theaters early, reducing deaths per capita by 50% vs. Philadelphia.
03
U.S. Public Health Service distributed gauze masks to 8 million people.
04
Quarantine of ships prevented spread to Australia until 1919.
05
Red Cross mobilized 20,000 nurses; volunteers sewed 1 million masks.
06
No effective antiviral; public urged rest, hydration, and isolation.
07
Propaganda posters promoted "Spitless Sal" and anti-spitting campaigns.
08
WHO later cited 1918 as model for non-pharmaceutical interventions (NPIs).
09
Vaccine trials failed; bacterins targeted wrong pathogens.
10
U.S. Surgeon General Rupert Blue issued nationwide closure guidelines.
11
Contact tracing rudimentary; households isolated for 7 days.
12
1918 led to Influenza Division at NIH for future surveillance.
13
Lessons informed 2009 H1N1 response with faster vaccine development.
14
Global health cooperation spurred post-1918, precursor to WHO.
15
Modern reconstructions used for universal flu vaccine research.
16
Pandemic spurred epidemiology advances, like Wade Hampton Frost's work.
17
U.S. states varied: California strict, Pennsylvania lax initially.
18
Samoa's failure to quarantine ship led to WHO maritime protocols.
19
1918 data used in models predicting COVID-19 impacts.
20
Antiviral stockpiles now standard due to 1918 unpreparedness.
21
Public compliance high initially, but "mask slacker" arrests occurred.
22
The 1918 pandemic prompted the first global pandemic treaty discussions in 1920s.
23
Genomic sequencing of 1918 virus enabled mRNA vaccine tech advancements.
24
U.S. mortality dropped 30% in cities with early NPIs per Taubenberger analysis.
25
Legacy includes annual flu shots tracing to 1918 virology breakthroughs.
Interpretation
Public Health Response And Legacy Interpretation
The public health response to the Spanish flu relied heavily on community measures and logistics, from 8 million gauze masks distributed by the U.S. Public Health Service to 20,000 Red Cross nurses and 1 million masks sewn by volunteers, alongside targeted actions like St. Louis closing schools and cutting deaths per capita by 50 percent versus Philadelphia.
Reference
Cite This Report
This report is designed to be cited. We maintain stable URLs and versioned verification dates. Copy the format appropriate for your publication below.
APA
Margot Villeneuve. (2026, February 13). Spanish Flu Statistics. Gitnux. https://gitnux.org/spanish-flu-statistics
MLA
Margot Villeneuve. "Spanish Flu Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/spanish-flu-statistics.
Chicago
Margot Villeneuve. 2026. "Spanish Flu Statistics." Gitnux. https://gitnux.org/spanish-flu-statistics.
Sources & references
26 datasets cited across this report