Todd Carlson
The 1918 Influenza Pandemic
The Influenza pandemic of 1918 was the worst public health disaster of the 20th century. The virus that became known as the Spanish flu killed more Americans than all 20th century wars combined and more died of this disease in two months than have been killed by HIV/AIDS in the past 25 years. The scope of this modern plague is nearly incomprehensible and its implications are still being felt in the modern day. The virus that ravaged the United States through the fall of 1918 dramatically altered the American psyche and continues to affect the way that we view, plan for and combat infectious disease.
Spanish Influenza was a particularly deadly strain of the influenza virus categorized as influenza subset A, H1N1. All seasonal influenza strains since 1918 have been descendants of this incredibly deadly virus. Although closely related to common flu, what separates the Spanish flu is its incredibly high rate of infection and high case mortality rate. The average seasonal flu has a case mortality rate <.1% while the 1918 flu had a case mortality estimated at 2.5%, twenty five times that of a normal flu (Taubenberger, CDC). The Spanish influenza also seemed to be far more contagious that any other flu in history, infecting an estimated one third of the total earth’s population. Some estimates have put the global death toll as a result of the Spanish influenza as high as 100 million people (Taubenberger, CDC). More information about the classification, genetics and function of the Spanish Flu virus can be found at
The most likely area of origin for the killer virus that became known as the Spanish flu is somewhere in southern Asia. Here, at its true source of origin a minor animal influenza virus mutated and developed the ability to infect and kill humans. This is nearly always the route of deadly influenza mutation. Viral mutation is the process of viral RNA breaking apart and changing and the behavior of the viral strain changing as a result. More information about this complex biological process can be found at From its original site of mutation from animal to human the virus spread across the earth rapidly but was not particularly deadly in its earliest wave.
The first known outbreak of Spanish Influenza in the United States occurred at an army camp in Fort Riley Kansas which happened to be in close proximity to a pig farm. Although only a theory, many believe that the virus was being carried by the pigs at this farm and made a jump to humans in the surrounding area. On March 11th of 1918 at 7am an army private reported to the camp infirmary complaining of headache, vomiting and sore throat. These symptoms are far from unusual but within hours 100 soldiers fell ill and by the end of the week 500 soldiers became ill and 48 died of what is then classified as pneumonia. These deaths are suspected to be the first in the United States attributed to the Spanish Flu but largely went unnoticed at the time by the outside world. Within weeks the soldiers who survive the virus at Fort Riley were shipped off to Europe to fight in the First World War. After the Fort Riley outbreak the virus seemed to slacken in its intensity and severity until the following autumn although still moving through the population as a more minor infection similar to an ordinary seasonal flu. This first outbreak is considered the “first wave” of the viral epidemic and only a precursor to the second, far more serious wave.
Seasonal influenza poses a perennial threat to Americans but is often considered more of a nuisance than a true danger to life. Annually the flu kills 36,000 people in the US which is significant but not tremendous when it’s considered that in any given year 5% to 20% of all Americans are infected with the flu. Nearly all of the individuals who die of the flu in an average year are compromised by severe preexisting health conditions, elderly or the very young (Taubenberger, CDC).
Normally it is almost unheard of for young, heath people to die of the flu; this was not the case in regards to the 1918 Spanish flu. The 1918 Flu killed young, healthy people with ease and regularity as was shown by its first outbreak in Fort Riley. In Fort Riley the disease killed 48 out of 500 infected people (Influenza 1918). This rate of mortality of 9.6% is incredibly high especially when it’s considered that all the individuals killed were young, health males with a steady diet, no serious preexisting health conditions, adequate sanitation and readily accessible medical care. This trend that began in fort Riley followed the disease through the global pandemic as a major proportion of those killed were young and healthy between the ages of twenty and forty years old. This trend in the mortality rate represents a W shaped curve that is close to the U shaped curve normally seen in the seasonal flu except there is a spike in the mortality rate for people in the younger stage of life.
See fig.1

Graph courtesy of Centers for Disease Control
This graph shows the stark contrast in the specific death rate for individual according to age in comparison with that of previous seasonal influenzas.
A major reason why the Spanish influenza of 1918 killed young people so easily has to do with the way the virus’ pathology. The virus worked by attacking the body in such a way as to stimulate a massive response from the body’s immune system. The massive immune response created by the body is what actually killed people as the body attempted to destroy the infection by raising temperature in the form of fever and secreting fluid into the lungs in an effort to purge out the virus. This pneumonia (fluid collection in the lungs) was the main agent of death in regards to the virus as victims in fact died due to drowning on the body’s own fluids. If this initial pneumonia didn’t result in death the lingering fluid would often become infected causing a massive bacterial pneumonia that would eventually result in sepsis and death. This all means that the virus’s pathology essentially forced the body’s immune system to destroy itself and therefore individuals with a heartier immune system such as young people would have all the viruses affects worsened. This affect is certainly apparent but in regards to the very old and very weak the virus still exacted a very heavy toll as shown by the graph but the mortality rate for these older people is still slightly below normal for a seasonal flu.
Another contributing theory to the reason the 1918 Spanish flu killed so many young people has to do with an early, less severe influenza epidemic. A virus very similar to that of the Spanish flu known as the Russian Flu swept through Europe and the United states in 1889 and then faded away. Individuals born after 1889 would not have been exposed to this virus and their bodies would not have had the chance to create antibodies to fight it. This means that in 1918 a large proportion of the population over 35 years of age already had antibodies that could have more efficiently fought off the Spanish Flu or even made them totally immune. Younger people whose bodies had not been exposed to the Russian Flu totally lacked the benefits it may have granted. This theory is unproven and cannot fully explain the reasons why Spanish Flu killed so many young people but it is held in high regard as most likely a contributing factor (Taubenberger, CDC). More information about the contributing factors to viral immunity in regard to the Spanish flu can be found at
The seasonal flu that we experience now also has its affect offset by the widespread use of seasonal flu vaccines that are formulated yearly by the United States Center for Disease Control to combat the specific variant of the influenza virus that they anticipate to see in a given season. The people of the United States did not have the advantage these vaccines in 1918.
Modern medicine had made leaps in combating infectious disease in the decades leading up to 1918. Breakthroughs like the advent of the optical microscope and pasteurization meant that humans could now see and combat bacterial growth. These new techniques where revolutionary and tremendously beneficial to public health in the early 20th century but could do nothing to stop the Spanish Flu pandemic. The reason for this is that the scientific community in 1918 lacked the ability to image and combat viruses, the cause of the flu (Influenza 1918).
Throughout the pandemic the medical community in the United States tried in vain to stem the tide of death through the use antibacterial drugs that had no affect on the viral cycle of life. In the fall of 1918 a “vaccine” was created and sent to San Francisco, a place the virus had not manifested thus far but was expected to. The tonic that was created was designed to combat bacterial infection but had no affect on the virus and within weeks San Francisco was ravaged by the virus like so many other cities across the United States. This episode was tremendously demoralizing both to the public and the scientific community as the entire country seemed helpless in fighting the epidemic.
The autumn of 1918 was the deadliest time in the history of the United States and October was its deadliest month. In the first week of October 1918 in Philadelphia the death rate was 700 times that of the same week the year before. By the end of October 11 thousand people would die in Philadelphia alone. Across America 195,000 individuals died in 31 days. This month represents the climax of the disaster as the virus exerted its full potential on the US population.
In this most deadly time the social structure of the United States was on the brink of collapse. The American economy at this time experienced an unprecedented slump in an intense production oriented wartime economy as factories and stores shut down as a result of disease. Governments across the country in nearly all municipalities outlawed public gathers of all types and enacted laws to require people to wear masks in public, all in an effort to stem the tide of influenza infection. The masks worn by the public during the pandemic may have had some affect on the virus’s spread but if they did it was most likely very small. The paper masks of the day where so porous that they did very little to stop the tiny fluid droplets containing virus particles from escaping when an individual coughs (Influenza 1918).
Although the National, State and Local governments of the United States took measures to prevent infection the majority of the actions taken came too late to have tremendous affect on the virus’ spread. Many of the government’s actions during this disaster actually inadvertently contributed to the epidemic. The wartime activities of draft calls and support parades worked in direct opposition the practice of viral containment. Early on, as the virus slowly spread about the country towns all over the US held festivals and parades to show support for American soldiers heading across the Atlantic to fight in the First World War and the national government held draft calls where young men packed tightly into schools to sign up for military service. These large gatherings became a massive venue for people to mix and spread the deadly virus through the population. At this time the entirety of the governments focus was on achieving victory in Europe and not containing a spreading killer virus (Influenza 1918).
Contributing to this lack of focus on the epidemic was a widespread naïve attitude toward infectious disease. The government and people of the United States had a false sense of security brought on by the recent advancement in medicine. People simply could not image a disaster of this magnitude striking and killing so many people.
The highly contagious nature of the Spanish Flu was one of the key factors in the deadly nature of the disease. Airborne diseases like influenza are especially hard on caretakers as family members take time to aid loved ones suffering from the disease and are then almost always infected themselves. This was especially true in early 20th century America as the primary caregivers in nearly all medical situations were close family members, highly susceptible to infection themselves. This factor of infection spreading to immediate family members would still be a major issue today should another influenza pandemic like that of 1918 appear. Even today if a major disease stuck the United States hospitals would quickly become overwhelmed and individuals would have no choice but to remain at home and be provided care by family members. These family members would be at extreme risk of infection now just as they were in 1918 (Pandemic Influenza).
As the virus entered its worst stages in the fall of 1918 and the social structures of American life showed signs of crumbling hysteria began to reign over the population. Many instances of suicide where reported and one man in San Francisco was shot by a police officer in public for not wearing a mask. All over the country the wartime patriotism and energy that had been present only months before seemed to have vanished. Many individuals from the period explained that the flu all but destroyed intimacy and friendliness in the American culture. When the source of danger is your fellow human being many people lost the will to interact with one another or were too afraid of infection to be friendly or welcoming (Influenza 1918).
Survivors of the epidemic point to this aspect of dehumanization as one of the most damaging and crippling parts of the pandemic. This characteristic is unique to infectious disease pandemics because the source and nature of the danger presented fundamentally breaks down social support systems. When floods, hurricanes and tornadoes strike communities they destroy infrastructure and lives but pull survivors together into a more tightly knit group with the goal restoring normal life. By contrast when an infectious disease pandemic devastates a community the buildings and infrastructure are left intact and many die but instead of pulling together into tightly knit groups the survivors splinter and avoid gathering for fear of infection.
October of 1918 was the single deadliest month in American history but all of a sudden, as quickly as the virus had arisen, it vanished. The signing of the November 11th armistice ended the First World War and by mid November flu related deaths were a fraction of what they had been only weeks prior. In many cities in the United States life was largely back to normal by thanksgiving of 1918. The reason for this sharp decline is that the virus simply ran out of eligible hosts and could no longer continue. Everyone who was going to get the disease had already recovered and was now immune or was dead. For this reason the virus could no longer sustain its life cycle and spread through the population.
Major focus has been shifted to study of the 1918 Spanish Influenza pandemic recently as the world has felt the fear of new pandemics. Agents such as Avian Flu, Swine Flu and SARS (Severe Acute Respiratory Syndrome) have killed some and frightened millions but the question remains; what will happen if and when a new global pandemic strikes?
Predicting the social reaction to a new pandemic is a difficult and multi faceted ordeal. Modern America is strikingly different to than the America of 1918 but many similarities are present. Much like in 1918 a pandemic of major proportion would quickly overwhelm the all available hospital beds and devastate the medical community as they lack the resources to cope with a massive contagious disease epidemic. The medical community is fully aware of this shortcoming and has created contingency plans to remedy the problem, such as plans to create temporary tent style hospitals and expand capacity but these plans can only partially abate the problem of overwhelming case numbers. Maintaining a healthcare system that could handle a disaster of this magnitude would simply be unfeasible. This in combination with other problems like quarantine and healthcare workers not showing up to work due to the sickness of themselves or a loved one means that our already understaffed medical community would be overwhelmed within the first days of a pandemic and the American public would be left with little assistance, much like they were in 1918.
The CDC spends millions of dollars and man hours every year creating vaccines to protect the public from the seasonal flu or hybrid flues such as the avian flu classified as H5N1 and H7N7 as well as the swine flu also classified as H1N1. More information about these viruses can be found at
The Vaccines created for these viruses are usually very affective and would be a major tool in our arsenal for fighting a future influenza outbreak. Although normally affective these vaccines are based on educated guesses about the nature of the strain of influenza that is expected to appear. If the estimation is substantially wrong and the vaccine is ineffective or if a virus is of a strain that rapidly mutates and was therefore impervious to vaccine much of the public would be left with substantial vulnerability to infection. Additionally influenza vaccines are still produced in a painstaking process involving growing the virus inside chicken eggs. This method of production means that vaccines are produced in relatively low numbers and the process requires months. In a major pandemic outbreak, especially an unexpected one, vaccine could not be produced quickly enough to vaccinate a large amount of the population. The CDC already has recommended protocols for who will be vaccinated first in the event of a major pandemic. Among the first to be vaccinated would be healthcare workers and essential personnel followed by at risk population such as elderly people and the very young. This protocol of vaccination is essential but means that may who want the vaccine will not have it available to them. These individuals without the aid of a vaccine would be left in a position of vulnerability much like that of the population in 1918. A wealth of information on government pandemic protocols can be found at
The CDC and World Health Organization are constantly on the lookout for the next killer pandemic, searching the world and watching disease trends trying to identify the next killer flu so that it can be attacked early on as to avert a major global pandemic. Study of the 1918 Spanish Flu has been instrumental in this search. Bodies of people who died of the Spanish Flu have been exhumed from permafrost in Alaska and Siberia in an effort to collect and analyze the virus. These efforts have yielded a full genome for the 1918 Spanish influenza. This complete genome can be compared to emerging viruses in order to analyze them and predict their affects on humans so that their dangers can be assessed and proper steps can be taken to protect the public.
The lessons learned from study of the great Influenza Pandemic of 1918 are invaluable for the protection of the American public in the years to come. Analyzing the social aspects of past disasters is our best method for predicting and managing future catastrophes like disease pandemics.

Works Cited Page
Becker, Arielle. "Remembering the Lessons of 1918's Spanish Flu Outbreak." Hartford Courant (2009): n. pag. Web. 6 Dec 2009. <>.
"Influenza 1918." Web. 20 Nov 2009. <>.
"Pandemic Influenza." april 2007. Web. 4 Dec 2009. <>.
Taubenberger JK, Morens DM. 1918 influenza: the mother of all pandemics. Emerg Infect Dis [serial on the Internet]. 2006 Jan [date cited]. Available from