The costs associated with influenza include direct healthcare costs, indirect costs such as lost productivity, and intangible cost of pain, grief and social disruption. In general, 'cost of illness' refers to all costs that are borne by society. This includes factors such as loss of productivity in the work force and loss of income by the patient, which results in a loss of tax revenues and an inability to purchase the goods and services that drive the economy. The important point is that everyone in society bears the cost - healthcare providers, patients, third-party payers, and business and industry.
Adapting data on health economics to individual countries is not an easy task as differing local practice patterns in the treatment and management of influenza are potential problem areas which need to be considered carefully.

• On average over 400,000 general practitioners consultations annually are attributable to influenza and influenza-like-illness in England and Wales. The excess of over 11,000 elderly respiratory hospital admissions in England during epidemics of influenza costs the UK health service over £22 million every winter. It is estimated that in the UK in excess of 6 million working days are lost associated with certified influenza illness.
• In addition to the direct costs of medical care, the indirect costs of influenza are substantial and stem largely from absenteeism and loss of work productivity. Estimates of the cost of influenza in the USA, France and Germany have shown that indirect costs can be 5-10-fold higher than direct costs. Other intangible costs associated with influenza include impaired performance, which can reduce reaction times, and adverse effects on the quality of life of patients and their families.
• In France, of 817 assessable household contacts, 313 developed clinical influenza (secondary cases). The median duration of illness was 4-8 days and in working adults the mean number of workdays lost ranged from 0.3 to 4.0.
• During the 1995-96 season confirmed cases of influenza in Germany show that the average direct costs of the disease are US$100 and indirect costs US$862 per patient. This means that the 2,885 cases of influenza reported for Germany resulted in total costs of at least US$2.8 million. The true direct costs will be much higher if the costs of hidden influenza morbidity are taken into consideration. With indirect costs evaluated as US$862 per patient, estimates of lost productivity in Germany in 1995/96 were over US$900 million.
• In Austria, in 1990, a total of 3,808 patients with influenza were hospitalized for treatment (49/100,000). The 3.808 patients spent a total of 34,684 days in hospital. The overall costs of hospital treatment were some €7.5 million --per patient on average approx. €1,900; per pneumonia patient approx. €4,400.
• In Finland the average annual rate of influenza was highest (179 cases/1000 children) among children < 3 years old. For every 100 influenza-infected children < 3 years old, there were 195 days of parental work loss (mean duration, 3.2 days)
• In 3771 children less than 14 years of age with no chronic medical conditions who presented with a respiratory tract infection influenza virus was demonstrated in 352 cases (9.3%) in Italy. Parents and siblings of influenza positive children had more respiratory illnesses, received more antipyretics and antibiotics, needed more medical visits, missed more work or school days, and needed help at home to care for the ill children for a longer period of time in comparison with the influenza negative children.
• In the US the annual direct medical costs (hospitalization, doctors’ office visits, medications, etc.) of influenza are estimated at up to $4.6 billion. Furthermore, each year, up to 111 million workdays are lost because of influenza and this costs American businesses more than $7 billion a year in sick days and lost productivity. Total direct and indirect costs (work days lost, school days lost, etc.) of a severe influenza epidemic are at least $12 billion.