Influenza Timeline

Back to Orthomyxoviridae Home 

Influenza Events in the 20th Century

For a more complete timeline, including events from 1357 to 2008, visit the Orthomyxoviridae Timeline.

1918:"Spanish Flu": 1st pandemic of the 20th Century

On March 11, 1918, an Army private reports to the camp hospital at Fort Riley Kansas with symptoms. Soldiers with similar complaints enter the ward, and over 100 soldiers are admitted by noon. This number increased to 500 by the end of the week. The flu spread throughout the world during the summer, and this global transmission is exacerbated by the travel and contact of World War I. By September, the Surgeon General sends out a press release advising bed rest, good food, salts of quinine and aspirin for influenza patients. U.S. politicians blame the pandemic on the Germans, although the Germans are of course not spared by the disease. Around the country, schools, churches and other public gatherings are closed and canceled as social distancing policies are implemented. Although many cities, including San Francisco, Boston, Philadelphia and New York were denying the threat, presence, or severity of the pandemic in their area, each city is hit hard. In October, New York reports 851 influenza deaths in a single day, and Philadelphia's death rate is 700 times higher than normal. October's total death toll around the country is 195,000 attributed to influenza. Although World War I ends in November, influenza rages on in the U.S., and throughout the world. By the end of the pandemic, an estimated 20-100 million people were dead, surprisingly mostly previously healthy young adults. The pandemic is now attributed to an H1N1 virus.

1930: Richard Shope isolates influenza from pigs
Richard Shope first shows that swine influenza can successfully be transmitted through filtered mucous, thereby suggesting that the infectious agent is a virus. He later isolates the influenza virus from pigs, and publishes his findings in a 1936 paper.
1933: Influenza isolated from humans
Sir Christopher Andrewes is credited as being the first person to islate influenza from humans, with the help of Wilson Smith and Sir Patrick Laidlaw.
1940: Influenza grown on eggs
Frank Macfarlane Burnet successfully grows influenza in embryonated chicken eggs, becoming the first to do so on a laboratory growth system.
1941: Rapid influenza assay invented
George K. Hirst develops a new rapid assay for the influenza virus with his discovery that the virus causes hemagglutination of red blood cells.
1955: "Myxovirus" term created
Sir Christopher Andrewes (credited with influenza isolation from humans), Burnet (credited with the growing of the virus on a laboratory growth system) and Bang develop the term "myxovirus" for the family of viruses that contain influenza.
 1957: "Asian Flu:" 2nd pandemic of 20th Century
This pandemic was caused by an H2N2 virus, and began in China. An outbreak was first identified in February 1957. Vaccine production was initiated in May, and surveillance was increased around the world. A vaccine was available, although in very limited quantities, in August. In the U.S., it is thought that the virus was spread by schoolchildren who were spreading it in their classrooms and taking it home to their families. This hypothesis arrives from the fact that the epidemic started in the United States around September, when children were returning to school after summer. Also, infection rates were highest in children of school-attending age, as well as pregnant women, but the highest mortality rates were in the elderly. The peak of the epidemic in terms of mortality rates was between September 1957 and March 1958, with the first wave occurring in September/October, and the second wave occurring in January/February. By the end of the pandemic, over one million people were dead worldwide, and about 69,800 Americans were included in this death toll.
1968: "Hong Kong Flu:" 3rd pandemic of the 20th Century
This pandemic was caused by an H3N2 virus. This particular strain caused relatively low mortality because the N2 protein had been seen only one decade before, and an H3 virus had already spread around the world at the beginning of the century, offering some immunity. Not surprisingly, the "Hong Kong Flu" was first reported in Hong Kong in early 1968. The virus spread throughout the world, finally reaching the U.S. by September. Despite the spread, the peak of the epidemic was not observed until December. In the U.S., December 1968-January 1969 saw the highest death rate, with mostly elderly victims. By March, the epidemic was dwindling, with a total of 33,800 American deaths. A second wave hit the US in 1970, but was even more mild.
1976: The Swine Flu Incident
In 1976, an H1N1 virus was discovered to be the causative agent in the death of a soldier at Fort Dix, New Jersey. Because the 1918 epidemic was H1N1, and because it was thought to have started at an army base in the U.S., officials were very worried about a pandemic like that of 1918. As a result, President Gerald Ford calls for an emergency vaccination program in which a vaccine is hurriedly made and administered to nearly 25% of the American population. 1976 – Swine flu breaks out among a handful of soldiers stationed at Fort Dix, N.J. One dies. It's an H1N1 virus, and health officials worry that they are seeing the return of the 1918 H1N1 Spanish Flu pandemic. As the virus is circulating among U.S. pigs, President Gerald Ford calls for a crash vaccination program. Despite delays, a vaccine is made and a quarter of the U.S. population is inoculated. In the end, the swine flu never left the Fort Dix area, and 25 people died from Guillain-Barre syndrome, a rare complication of the vaccine.
1977: H1N1 strikes again
The H1N1 virus is found in May 1977 in northern China, and spreads worldwide by January 1978. This strain had not circulated since 1957, so anyone born after 1957 had no immunity. For this reason, most of the severe cases were in children and young adults under the age of 23.
1997: First human death from bird flu
May 1997 sees the first person to catch, and subsequently die from the novel H5N1 bird flu. The death occurs in Hong Kong, and an outbreak ensues. A few hundred people are known to have been infected with H5N1 in Hong Kong in 1997, with 18 hospitalizations and 6 deaths. This virus is particularly alarming to scientists and public health officials because it can move directly from birds to people, instead of relying on a pig as the mixing vessel. Also, most of the victims are young adults, much like in the 1918 epidemic. 1.5 million chickens are destroyed in Hong Kong, and no new human infections are reported during the year.