Behavior change may have the greatest influence on waves of influenza outbreak

Three waves of the deadliest influenza pandemic in history, known as the Spanish flu, hit England and Wales in 1918, just as World War 1 was coming to an end.

Why flu arrives in multiple waves like this is the focus of a study by McMaster University researchers who discovered three contributing factors: the closing and opening of schools, temperature changes and – most importantly – changes in human behavior.

"We found all three factors were important in 1918 but that had the largest effect," said David Earn, an investigator with the Michael G. DeGroote Institute for Infectious Disease Research, and a professor in McMaster's Department of Mathematics and Statistics.

The study appears in the July 10 online issue of the Proceedings of the Royal Society B.

The researchers did not measure behavioural change directly; instead, their model showed that the three waves could only be explained if people reduced infectious contact rates when recent influenza mortality was high. Possible mechanisms include avoiding large gatherings, keeping distance from other people, and hand-washing.

The study's findings are significant as global health officials keep watch on an emerging virus, Middle East Respiratory Syndrome (MERS), which is said to be more deadly than Severe Acute Respiratory Syndrome (SARS) and has already spread from Saudi Arabia to France, Germany, Italy and Britain. Dr. Margaret Chan, director-general of the World Health Organization, has called MERS a "threat to the entire world".

To investigate factors underlying the three-wave shape of the 1918 , McMaster researchers developed what they describe as a simple epidemic model. It incorporates three factors in addition to natural disease spread: school terms, temperature changes during an outbreak and changes in human behavior.

To collect information, researchers scoured available historical documents and collected data about weekly influenza deaths.

The paper concludes that behavioral changes of people, temperature trends and school closure all contributed to the three-wave mortality patterns in the UK during the 1918 with behavioral changes having the greatest effect.

Earn conducted the study with his colleague Dr. Jonathan Dushoff, associate professor, Department on Biology, and researchers at Hong Kong Polytechnic University, Queen's University and the University of Victoria.

More information: Inferring the causes of the three waves of the 1918 influenza pandemic in England and Wales, rspb.royalsocietypublishing.or… .1098/rspb.2013.1345

Related Stories

Two new MERS deaths in Saudi: ministry

Jul 07, 2013

A Saudi man and a child have died from the MERS virus, bringing the number of deaths from the respiratory infection in the kingdom to 38, the health ministry said on Sunday.

School closures slow spread of pH1N1: study

Feb 06, 2012

Closing elementary and secondary schools can help slow the spread of infectious disease and should be considered as a control measure during pandemic outbreaks, according to a McMaster University led study.

Saudi declares new death from MERS virus

Jun 24, 2013

A Saudi man has died from the MERS virus, bringing the kingdom's death toll from the SARS-like infection to 34, the ministry of health said on Monday.

Recommended for you

WHO: Number of Ebola cases passes 10,000

1 hour ago

The number of people believed sickened by Ebola has passed 10,000, according to figures released Saturday by the World Health Organization, as the outbreak continues to spread.

NY and NJ say they will require Ebola quarantines

13 hours ago

The governors of New Jersey and New York on Friday ordered a mandatory, 21-day quarantine for all doctors and other arriving travelers who have had contact with Ebola victims in West Africa.

User comments