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Social and Economic Impact of Influenza

Economic impact

In addition to its social impact, influenza also has a significant economic impact, including lost or reduced productivity in the work place or at home due to incapacitating illness, and increased health-care costs from treating the disease. Accordingly, the economics of influenza are concerned primarily with two issues: the economic impact of influenza and the cost of interventions to prevent or treat influenza.

Understanding the economics of influenza

The economic impact of disease is often measured by conducting a cost-of-illness study, which estimates the overall cost of the disease, including its treatment and consequences. These costs can be classified into three separate types:

  • Direct costs – these are actually incurred monetary costs, and imply a cash outlay (acquisition costs, fees, charges).
  • Indirect costs – these are not paid in cash but can be inferred, as they arise from reduced or lost productivity due to work absenteeism, decreased performance or even premature death.
  • Intangible costs – these are attributable to pain, suffering and reduced quality of life. Avoidance of these is often identified as an intangible benefit. These costs cannot be easily converted to a monetary value.

In influenza, the cost of prevention or treatment strategies, such as influenza vaccination programmes, may be measured using cost–effectiveness analyses or cost–benefit analyses. These analyses of influenza-related health-care interventions measure whether the benefits derived from the intervention are worth the cost of undertaking the intervention.

The costs of the intervention are typically measured from the perspective of the payer (e.g. health-care system) and include the direct cost of the intervention itself. The benefits, on the other hand, can include direct, indirect and intangible costs resulting from the intervention. These may include reduced hospitalizations and physician visits, reduced work or school absenteeism, reduced mortality and improved quality of life. Reduced health-care visits can provide a cost saving to the health-care payer. Reduced absenteeism at work is an indirect benefit to the employer and society. Reduced mortality and improved quality of life is an intangible benefit that is gained by the individual, their family and friends, and society at large.

Economic evaluations estimating the cost-effectiveness of programmes should always compare one health-care strategy against another. For example, when estimating the cost-effectiveness of influenza vaccination, the analysis may compare the expected overall cost and benefits of no vaccination against the expected costs and benefits resulting from an influenza vaccination programme. The decision-maker would then be presented with the additional costs of the vaccination programme and determine if it is worth the additional cost given the additional benefits it provides during the influenza season.

The results from such analyses are usually presented in the form of an incremental cost-effectiveness ratio (ICER), which shows the additional cost of providing the intervention per extra additional unit of benefit. This can be illustrated with a simple hypothetical example. Suppose a programme to vaccinate 1000 people costs &z.euro;100,000. The vaccination reduces health-care resource use, saving the health-care payer &z.euro;50,000. Furthermore, by reducing the number of people with influenza, the programme also avoids five deaths relating to influenza. Therefore, the ICER would be:

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If the decision-maker would normally be prepared to pay more than &z.euro;10,000 to save a life, the programme would be deemed a cost-effective option. If the programme can avoid more costs than it costs to implement, and it saves more lives, then the programme is always cost-effective as it provides more benefit and saves money.

A cost–benefit analysis converts all effectiveness benefits, including intangible costs, into a monetary value. In the example above, the decision-maker may value a life saved at &z.euro;30,000. Consequently, the monetary benefit of the programme is &z.euro;50,000 (health-care savings) plus &z.euro;150,000 (five lives saved at a value of &z.euro;30,000 each). This total monetary benefit of &z.euro;200,000 outweighs the &z.euro;100,000 cost of implementing the programme. The programme would therefore be deemed cost-effective and should be implemented.

Cost of illness

The increasing cost of health care has prompted research to quantify the cost of illness due to influenza. Cost-of-illness research is the first step in resource allocation decision-making. It results in an increased awareness of the impact of infection, it determines the burden of disease in relation to other diseases, it defines the unmet medical need which future drug development should address, and it facilitates the formulation of prevention, vaccination and treatment policies. Cost-of-illness research is hampered by underestimates of the incidence of the disease due to influenza and difficulties quantifying indirect and intangible costs. A study in France has shown that the cost of influenza was up to US $20 billion during the 1988/89 epidemic ( Table 11 ). 9, x E Levy. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 9 (Suppl 3) (1996) (62 - 66) Crossref. 10 x TD Szucs. Influenza. The role of burden-of-illness research. Pharmacoeconomics 16 (Suppl 1) (1999) (27 - 32) Crossref.

Table 11 Estimated cost of an influenza epidemic in France in 1989. source: Adapted from Levy E. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 1996; 9 (Suppl 3): 62–66 9 x E Levy. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 9 (Suppl 3) (1996) (62 - 66) Crossref. with permission from Adis International.

Estimated cost of an influenza epidemic in France in 1989
1989 (French francs, millions) 2005 equivalent (&z.euro;, millions)
Costs National health insurance system Society National health insurance system Society
Direct medical costs
 • GP visits 363.95 494.20 423.93 575.65
 • Medication 350.69 637.61 408.49 742.70
 • Hospitalizations 92.39 115.49 107.62 134.52
Total direct medical costs 807.03 1247.31 940.04 1452.87
Indirect costs
 Cost of absenteeism and loss of productivity 1121.30 13,076.00 1306.10 15,231.11
Total costs 1928.33 14,323.31 2246.14 16,683.98

References in context

Direct costs

The direct costs of influenza have been estimated in a number of different studies. These vary depending on the structure of the national health services. Physician visits act as the main cost driver. In the USA, influenza affects approximately 50–60 million people annually, of whom about 50% visit their doctor. 11 x RB Couch. Influenza: prospects for control. Ann Intern Med 133 (2000) (992 - 998) Most of these 25–30 million physician visits are by schoolchildren and young adults. Between 114,000 and 142,000 (2.1–2.6 per 1000) of those infected are hospitalized, mainly very young children (5 per 1000) and elderly people (3–4 per 1000). 12 x CDC. Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 50 (RR-4) (2001) (1 - 46) The annual direct medical costs of influenza in the USA are estimated at between $3 and $5 billion. 13 x PA Patriarca. New options for prevention and control of influenza. J Am Med Assoc 282 (1999) (75 - 77) Crossref.

Indirect costs: work productivity loss and school absenteeism

During influenza outbreaks, there is a significant rise in absenteeism in the working population. Indeed, the most significant cost of influenza to society is the indirect cost related to lost productivity and work absenteeism. Reported studies of work loss due to influenza range from 0.79 to 4.9 days of work lost. 14 x KL Nichol. Cost-benefit analysis of a strategy to vaccinate healthy working adults against influenza. Arch Intern Med 161 (2001) (749 - 759) Crossref. From a UK study, the mean time off work for health-care workers with influenza was 4 days. 15 x A Elder, B O'Donnell, E McCruden, et al.. Incidence and recall of influenza in a cohort of Glasgow health care workers during the 1993–4 epidemic: results of serum testing and questionnaire. Br Med J 313 (1996) (1241 - 1242) Crossref. However, it has been also been noted that health-care workers tend to continue to work during their illness. 16 x J Wilde, J MacMillan, J Serwint, et al.. Effectiveness of influenza vaccine in health care professionals: a randomised trial. J Am Med Assoc 281 (1999) (908 - 913) Crossref. From the National Health Interview Survey in the USA, influenza was responsible for more than 200 million days of restricted activity, 100 million days of bed disability, 75 million days of lost work and 22 million health-care provider visits across the USA in 1995. 14 x KL Nichol. Cost-benefit analysis of a strategy to vaccinate healthy working adults against influenza. Arch Intern Med 161 (2001) (749 - 759) Crossref. Surveillance programmes have found that the high absenteeism in the work place is common during peak influenza activity, typically between December and March. 17 x JH Dille. A worksite influenza immunization program. Impact on lost work days, health care utilization, and health care spending. AAOHN J 47 (1999) (301 - 309) Overall, influenza accounts for around 10% of sickness absence from work.

Estimates of the cost of influenza have shown that indirect costs can be as much as 10 times higher than the direct medical costs and range from $10 to $15 billion per year. 9, x E Levy. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 9 (Suppl 3) (1996) (62 - 66) Crossref. 10 x TD Szucs. Influenza. The role of burden-of-illness research. Pharmacoeconomics 16 (Suppl 1) (1999) (27 - 32) Crossref. This is illustrated in Table 11 , which presents the estimated direct and indirect costs of the moderate 1989 influenza epidemic in France. In this example, the indirect costs due to work absenteeism and loss of productivity from the societal perspective, account for the major part (91%) of the estimated cost of illness. Obviously, from the perspective of the French national health insurance ( Table 11 ), the indirect costs related to absenteeism and loss of productivity represent a much smaller share (58%).

Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place. In the general population, it takes 7 days on average to alleviate the major symptoms of ILI. 18 x JA Mauskopf, SC Cates, AD Griffin. A pharmacoeconomic model for the treatment of influenza. Pharmacoeconomics 16 (Suppl 1) (1999) (73 - 84) Crossref. From a review of the literature, Nichol concluded that workers with ILI took an average of 2 days off work. 14 x KL Nichol. Cost-benefit analysis of a strategy to vaccinate healthy working adults against influenza. Arch Intern Med 161 (2001) (749 - 759) Crossref. This was based on estimates in the literature ranging from 0.79 days 19 x C Bridges, W Thompson, M Melzer, et al.. Effectiveness and cost-benefit of influenza vaccination of healthy working adults. J Am Med Assoc 284 (2000) (1655 - 1663) Crossref. to 4.9 days. 20 x V Kumpulainen, M Makela. Influenza vaccination among healthy employees: a cost-benefit analysis. Scand J Infect Dis 29 (1997) (181 - 185) Crossref. Nichol et al . 21 x KL Nichol, et al.. The effectiveness of vaccination against influenza in healthy, working adults. New Engl J Med 333 (1995) (889 - 893) Crossref. estimated that for every 100 non-vaccinated employees, 52 working days were lost due to ILI. Campbell and Rumley 22 x DS Campbell, MH Rumley. Cost-effectiveness of the influenza vaccine in a healthy, working-age population. J Occup Environ Med 39 (1997) (408 - 414) Crossref. estimated the direct costs of medical care received for ILI at $22.80 per person, and the indirect costs at $80 to the company for each day's absence from work. Other estimates for the cost per working day lost are higher; for example, in Dille, 17 x JH Dille. A worksite influenza immunization program. Impact on lost work days, health care utilization, and health care spending. AAOHN J 47 (1999) (301 - 309) the cost per work day lost was estimated at $175.24.

Even a mild attack of influenza can reduce reaction times by 20–40%, 23 x AS Monto, KM Sullivan. Acute respiratory illness in the community. Frequency of illness and the agents involved. Epidemiol Inf 110 (1993) (145 - 160) Crossref. with associated health and safety implications among those who continue working despite influenza infection (up to half of employees). Workers who have ILI and either stay at work or return to work before the illness has disappeared have reduced effectiveness (lower productivity) while working. Keech et al . 24 x M Keech, A Scott, P Ryan. The impact of influenza and influenza-like illness on productivity and health care resource utilisation in a working population. Occup Med 48 (1998) (85 - 90) Crossref. calculated that workers, on average, returned to work 0.7 days before they should. As well as reduced effectiveness at work, there are additional burdens associated with making poor decisions when one is ill.

Burckel et al . 25 x E Burckel, T Ashraf, J Galvao de Sousa Filho, et al.. Economic impact of providing workplace influenza vaccination. A model and case study application at a Brazilian pharma-chemical company. Pharmacoeconomics 16 (1999) (563 - 576) Crossref. calculated mean attack rates for different levels of morbidity for various age groups based on information from Houston Surveillance and European evidence, assuming an overall attack rate of 10%. The 18–24 age group was found to be most likely to contract low-morbidity influenza in which normal work schedules are essentially maintained and the related impairment was equivalent to an average of one lost day of work. In moderate influenza morbidity, 3 days of work were lost for patients under 45 years and 4 days for those over 45 years. High-morbidity influenza was defined as influenza cases that require hospitalization with an average of 12 days of work lost. 25 x E Burckel, T Ashraf, J Galvao de Sousa Filho, et al.. Economic impact of providing workplace influenza vaccination. A model and case study application at a Brazilian pharma-chemical company. Pharmacoeconomics 16 (1999) (563 - 576) Crossref.

In a study of families with school-aged children during an influenza season compared with a non-influenza winter season, there was a significantly greater total number of illness episodes, febrile illnesses, analgesic use, school absences, parental absenteeism and secondary illnesses among family members. It was concluded that the influenza season has significant adverse effects on the quality of life of school-aged children and their families. 26 x KM Neuzil, et al.. Illness among schoolchildren during influenza season: effect on school absenteeism, parental absenteeism from work, and secondary illness in families. Arch Pediatr Adolesc Med 156 (2002) (986 - 991) Time off work due to children being away from school with influenza can also be an important factor. On average, 3 days of work are lost due to a child being absent from school because of influenza, requiring a parent to remain at home. 14 x KL Nichol. Cost-benefit analysis of a strategy to vaccinate healthy working adults against influenza. Arch Intern Med 161 (2001) (749 - 759) Crossref.

Intangible costs

Intangible costs include quality of life and impairment of function and performance. Influenza infection is stressful for the individual infected and frequently places a burden of care on other family members. This can restrict the usual activities of families and reduce the quality of life of the affected individual, as well as those around him/her. The socio-economic impact of these factors is difficult to quantify. In elderly people, in particular, infection is associated with a decline in major physical functions. 27 x WH Barker, H Borisute, C Cox. A study of the impact of influenza on the functional status of frail older people. Arch Intern Med 158 (1998) (645 - 650) Crossref.

 
x

Table 11 Estimated cost of an influenza epidemic in France in 1989. source: Adapted from Levy E. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 1996; 9 (Suppl 3): 62–66 9 x E Levy. French economic evaluations of influenza and influenza vaccination. Pharmacoeconomics 9 (Suppl 3) (1996) (62 - 66) Crossref. with permission from Adis International.

Estimated cost of an influenza epidemic in France in 1989
1989 (French francs, millions) 2005 equivalent (&z.euro;, millions)
Costs National health insurance system Society National health insurance system Society
Direct medical costs
 • GP visits 363.95 494.20 423.93 575.65
 • Medication 350.69 637.61 408.49 742.70
 • Hospitalizations 92.39 115.49 107.62 134.52
Total direct medical costs 807.03 1247.31 940.04 1452.87
Indirect costs
 Cost of absenteeism and loss of productivity 1121.30 13,076.00 1306.10 15,231.11
Total costs 1928.33 14,323.31 2246.14 16,683.98

References in context

References

Label Authors Title Source Year
9

References in context

E Levy. French economic evaluations of influenza and influenza vaccination. Crossref. Pharmacoeconomics 9 (Suppl 3) (1996) (62 - 66) 1996
10

References in context

  • The increasing cost of health care has prompted research to quantify the cost of illness due to influenza.
    Go to context

  • France.
    Go to context

TD Szucs. Influenza. The role of burden-of-illness research. Crossref. Pharmacoeconomics 16 (Suppl 1) (1999) (27 - 32) 1999
11

References in context

  • The direct costs of influenza have been estimated in a number of different studies.
    Go to context

RB Couch. Influenza: prospects for control. Ann Intern Med 133 (2000) (992 - 998) 2000
12

References in context

  • The direct costs of influenza have been estimated in a number of different studies.
    Go to context

CDC. Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 50 (RR-4) (2001) (1 - 46) 2001
13

References in context

  • The direct costs of influenza have been estimated in a number of different studies.
    Go to context

PA Patriarca. New options for prevention and control of influenza. Crossref. J Am Med Assoc 282 (1999) (75 - 77) 1999
14

References in context

  • During influenza outbreaks, there is a significant rise in absenteeism in the working population.
    Go to context

  • During influenza outbreaks, there is a significant rise in absenteeism in the working population.
    Go to context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

  • In a study of families with school-aged children during an influenza season compared with a non-influenza winter season, there was a significantly greater total number of illness episodes, febrile illnesses, analgesic use, school absences, parental absenteeism and secondary illnesses among family members.
    Go to context

KL Nichol. Cost-benefit analysis of a strategy to vaccinate healthy working adults against influenza. Crossref. Arch Intern Med 161 (2001) (749 - 759) 2001
15

References in context

  • During influenza outbreaks, there is a significant rise in absenteeism in the working population.
    Go to context

A Elder, B O'Donnell, E McCruden, et al.. Incidence and recall of influenza in a cohort of Glasgow health care workers during the 1993–4 epidemic: results of serum testing and questionnaire. Crossref. Br Med J 313 (1996) (1241 - 1242) 1996
16

References in context

  • During influenza outbreaks, there is a significant rise in absenteeism in the working population.
    Go to context

J Wilde, J MacMillan, J Serwint, et al.. Effectiveness of influenza vaccine in health care professionals: a randomised trial. Crossref. J Am Med Assoc 281 (1999) (908 - 913) 1999
17

References in context

  • During influenza outbreaks, there is a significant rise in absenteeism in the working population.
    Go to context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

JH Dille. A worksite influenza immunization program. Impact on lost work days, health care utilization, and health care spending. AAOHN J 47 (1999) (301 - 309) 1999
18

References in context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

JA Mauskopf, SC Cates, AD Griffin. A pharmacoeconomic model for the treatment of influenza. Crossref. Pharmacoeconomics 16 (Suppl 1) (1999) (73 - 84) 1999
19

References in context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

C Bridges, W Thompson, M Melzer, et al.. Effectiveness and cost-benefit of influenza vaccination of healthy working adults. Crossref. J Am Med Assoc 284 (2000) (1655 - 1663) 2000
20

References in context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

V Kumpulainen, M Makela. Influenza vaccination among healthy employees: a cost-benefit analysis. Crossref. Scand J Infect Dis 29 (1997) (181 - 185) 1997
21

References in context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

KL Nichol, et al.. The effectiveness of vaccination against influenza in healthy, working adults. Crossref. New Engl J Med 333 (1995) (889 - 893) 1995
22

References in context

  • Numerous studies have been conducted around the world estimating the indirect cost due to influenza-like illness (ILI) in the work place.
    Go to context

DS Campbell, MH Rumley. Cost-effectiveness of the influenza vaccine in a healthy, working-age population. Crossref. J Occup Environ Med 39 (1997) (408 - 414) 1997
23

References in context

  • Workers who have ILI and either stay at work or return to work before the illness has disappeared have reduced effectiveness (lower productivity) while working.
    Go to context

AS Monto, KM Sullivan. Acute respiratory illness in the community. Frequency of illness and the agents involved. Crossref. Epidemiol Inf 110 (1993) (145 - 160) 1993
24

References in context

  • Workers who have ILI and either stay at work or return to work before the illness has disappeared have reduced effectiveness (lower productivity) while working.
    Go to context

M Keech, A Scott, P Ryan. The impact of influenza and influenza-like illness on productivity and health care resource utilisation in a working population. Crossref. Occup Med 48 (1998) (85 - 90) 1998
25

References in context

  • Houston Surveillance and European evidence, assuming an overall attack rate of 10%.
    Go to context

  • Houston Surveillance and European evidence, assuming an overall attack rate of 10%.
    Go to context

E Burckel, T Ashraf, J Galvao de Sousa Filho, et al.. Economic impact of providing workplace influenza vaccination. A model and case study application at a Brazilian pharma-chemical company. Crossref. Pharmacoeconomics 16 (1999) (563 - 576) 1999
26

References in context

  • In a study of families with school-aged children during an influenza season compared with a non-influenza winter season, there was a significantly greater total number of illness episodes, febrile illnesses, analgesic use, school absences, parental absenteeism and secondary illnesses among family members.
    Go to context

KM Neuzil, et al.. Illness among schoolchildren during influenza season: effect on school absenteeism, parental absenteeism from work, and secondary illness in families. Arch Pediatr Adolesc Med 156 (2002) (986 - 991) 2002
27

References in context

  • Intangible costs include quality of life and impairment of function and performance.
    Go to context

WH Barker, H Borisute, C Cox. A study of the impact of influenza on the functional status of frail older people. Crossref. Arch Intern Med 158 (1998) (645 - 650) 1998

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