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​Pandemic History

There have been four major pandemics in humans since the beginning of the 20th Century, with up to 54 million people dying worldwide as a result.

Spanish Flu: The Great Pandemic of 1918-1919

The pandemic of 1918-1919 is a historical lesson on how devastating the flu virus can be. It is the most devastating pandemic ever recorded in human history, and the event by which all other pandemics are measured. Sometimes called the Spanish Flu, this pandemic was caused by an especially potent strain of the flu virus. At 50 million deaths, more people died in the Spanish Flu pandemic than were killed in World War I. An estimated 675,000 Americans were among the dead.

Unlike seasonal flu, which mostly threatens the health of the very young and elderly, the Spanish Flu caused serious illness and death in otherwise young, healthy people. During the Spanish Flu pandemic:

  • The average life span in the U.S. was decreased by 10 years.
  • Compared to previous years, during the pandemic, 15 to 34-year-olds were 20 times more likely to die of flu or pneumonia - a swelling of the lungs caused by infection,
  • People were struck with illness suddenly and died rapidly, sometimes within hours or overnight.
Pennsylvania was one of the states hardest hit by the pandemic in the U.S. Read more about the affects of the Spanish Flu in Pennsylvania from September 1918 through the summer of 1919.

Life in the United States During the Spanish Flu Pandemic

The Spanish Flu pandemic affected almost every part of American society. With one-quarter of the US infected, it was impossible to escape from the illness. As the disease spread, schools and businesses emptied. Telephone, mail, and garbage collection services stopped as workers became ill and could not do their jobs.

These disturbing facts about the Spanish Flu pandemic hint at the possible severity of a future pandemic, and why we must do what we can to prepare:

  • Infection and death rates were highest among adults 20 to 50 years old.
  • In Philadelphia, so many children were orphaned that the Bureau of Child Hygiene was overwhelmed and unable to care for them.
  • Because there were so many deaths, funerals were limited to 15 minutes.
  • Bodies piled up as the epidemic claimed life after life.
  • In addition to the lack of healthcare workers and medical supplies, there was a shortage of coffins, morticians, and gravediggers.
Learn more about the Spanish Flu of 1918-1919 through personal stories, letters, and telegrams written by survivors and family members of those who died.


H1N1, which was also called the swine flu, is a new strain of influenza first reported in the United States in mid-April, 2009. It is still spreading from person-to-person in some parts of the world. Because it is a new virus, people have little natural immunity to it and can catch it more easily. Although it can be serious, most people who have become ill from H1N1 recover without hospitalization or medical treatment.

The symptoms of H1N1 (including fever, cough and sore throat) are similar to the seasonal flu. However, H1N1 is different in some important ways:

  • People who are pregnant may be at even greater risk for complications from H1N1.
  • Although young adults are not normally affected as severely by seasonal flu, they are for H1N1. As a result, young adults should consider vaccination for H1N1.
  • So far, elderly people are considered to be at low risk for H1N1. According to the Centers for Disease Control and Prevention, H1N1 virus has been reported in only a few people older than 64.