Impact of Influenza
The impact of influenza on human society is most marked at the time of a pandemic; it has been estimated that in the 1918-19 Spanish influenza pandemic 2 million of Australia's population of 5 million were infected and 15,000 died. However, it is difficult to determine the true mortality rate due to influenza, particularly in non-pandemic years.
In 1847 William Farr, a doctor and statistician in the British Office of the Registrar-General, used the term "excess mortality" to describe the increase in deaths that he had shown to occur during the influenza season and which were attributed to causes other than influenza itself. This influenza-related excess mortality significantly outweighs that attributed to influenza. Statistical methods have been applied to estimating the true mortality due to influenza and, in the USA, it has been estimated to account for 36,000 - 41,000 deaths annually.
The World Health Oganization (WHO) estimates that between three and five million cases of severe illness and between 250,000 and 500,000 deaths occur every year around the world associated with influenza.1 Based on actuarial data from Australia and overseas observations, it is believed that there are some 1,500-2,500 influenza-related deaths annually in Australia.
In addition to the loss of life, annual influenza outbreaks represent a significant healthcare burden and cost to industry and to the individual. A recent study found that in Australia influenza2 :
- causes 18,000 hospitalisations
- requires over 300,000 GP consultations
- costs the Australian health care system at least $85m annually
In addition to this is the economic loss suffered by industry and individuals. An earlier study conducted over a decade ago estimated that 1.5 million work days are lost annually in Australia.3
1. WHO influenza fact sheet no 211. Found at http://www.who.int/mediacentre/factsheets/fs211/en/
Page publication: January 2014