The 1918 Flu Pandemic

You may vaguely recall something your parents or grandparents or great-grandparents said about the 1918 flu that killed well over 70 million people, maybe even some of your relatives. Called the Spanish Flu (but first noted in Canton, China), it appeared close to the heels of World War I with a mortality rate that was easily twice that of the entire multi-national conflict, including all civilian deaths. It has been estimated that nearly a billion people were infected, which was then about half the world's population. Some historians claim that the balance of power of the war was tipped by the flu, which struck countries of the Central Powers before it did those of the Allied Powers.

Most of its victims were healthy young adults, in contrast to most influenza outbreaks which predominantly affect juvenile, elderly, or otherwise weakened people. Scientists have since used tissue samples from frozen victims to reproduce the virus for study. (Given the strain's extreme virulence there has been controversy regarding the wisdom of such research.) Among the conclusions of this research is that the virus kills via a cytokine storm (overreaction of the body's immune system) which explains its unusually severe nature and the concentrated age profile of its victims. The responses of the strong immune systems of these young, otherwise healthy adults ravaged the body, whereas the response of the weaker immune systems of children and middle-aged adults caused fewer deaths. Deaths then in children and older adults contracting the flu were generally caused by secondary infections that resulted in bacterial pneumonia and other complications in that time when antibiotics did not exist, communication and transportation are not what they are today, and medical supportive care and infection control measures were comparatively primitive.

A large number of infections in the United States and other nations involved in World War I were seen in military settings, where thousands of age-succeptible virus hosts were closely housed and massive troop movement occurred. One soldier wrote home to his mother: "Since noon today our camp has been under quarantine to prevent an epidemic of Spanish influenza. We have had no cases thus far but it is the intention of the medical officers to prevent any case of the disease from making an appearance. All the men who have even slight colds have been put into separate barrack which, of course, were immediately christened 'the TB ward' by the rest of the company." That same day, he wrote to his brother, a Navy sailor at home awaiting orders: "Well the Spanish Influenza has made an appearance here and we are under strict orders no visits to Chattanooga, we are certainly the hard luck guys when it comes to this quarantine proposition."

Exact numbers of U.S. military members affected or killed by the flu are difficult to determine, as the War Department then downplayed (and likely attributed to other causes) the illnesses and deaths of servicemen and women during the March 1918-June 1920 pandemic. But given that most of the military population was of an age that was most at risk, and that the general population's flu death rate was easily 5 out of every 1000 people, the numbers are undoubtedly high.