Elsevier Health Sciences

Topics

« Back to Resource Center

Social and Economic Impact of Influenza

Social impact

In addition to the short-term incapacitating symptoms of influenza, complications may arise from having influenza either directly and indirectly (see Chapter 5 ). These complications have a large social impact, including increased demands on health-care systems, long-term illness and disability, or even mortality.

Key Messages

  • The WHO estimates that 3–5 million cases of severe influenza illness result in 250,000–500,000 deaths annually in the industrialized world.
  • Compared to healthy adults, influenza-related death rates are as much as 50- to 100-fold higher among patients with cardiovascular or pulmonary disease, and even higher for those with two or more co-morbid conditions.
  • In young children, influenza is associated with increased rates of otitis media and serious cardiorespiratory illnesses leading to hospitalization.
  • The annual cost of influenza is highly variable and may be as high as E20 million in direct health-care costs in some European countries – these direct costs are less than 10% of the total annual cost to society.
  • Work absenteeism from influenza illness results in indirect costs that may also be as high as E20 million in lost days of work in a single influenza season.
  • School absenteeism not only impacts on children but contributes on average to a loss of 3 work days for the parent who must remain at home with the child.
  • Intangible costs include those related to death, increased disability or a diminished quality of life for the individual and the potential additional burden to caregivers.
  • The Centers for Disease Control (CDC) has estimated that in the USA, during an influenza pandemic, high-risk individuals representing 15% of the population would account for ∼84% of all deaths, at a cost of US .3–166.5 billion, excluding disruptions to commerce and society.

Epidemiological records on the morbidity and mortality statistics related to influenza show that, in the winters from 1990 to 1998, the mean annual estimate of influenza-associated deaths in the USA was 51,203, mostly associated with influenza A (H3N2). 3 x WW Thompson, DK Shay, E Weintraub, et al.. Mortality associated with influenza and respiratory syncytial virus in the United States. J Am Med Assoc 289 (2003) (179 - 186) Crossref. The death rates varied from year to year, with an average across the decade of 195 influenza-related deaths per million population ( Table 8 ).

Table 8 Estimated annual influenza deaths rates per 100,000 in the USA (1990–1999). source: Reproduced from Thompson WW et al . Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA ; 289 : 179–186 3 x WW Thompson, DK Shay, E Weintraub, et al.. Mortality associated with influenza and respiratory syncytial virus in the United States. J Am Med Assoc 289 (2003) (179 - 186) Crossref. with permission from the American Medical Association.

Estimated annual influenza deaths rates per 100,000 in the USA (1990–1999)
Season A/H1N1 A/H3N2 B Total
1990–1991 0.79 2.41 7.00 10.20
1991–1992 2.57 18.11 0.22 20.90
1992–1993 0.46 7.75 7.42 15.64
1993–1994 0.07 18.88 0.16 19.10
1994–1995 0.22 12.91 2.72 15.85
1995–1996 5.58 8.94 2.84 17.36
1996–1997 0.00 20.98 4.73 25.71
1997–1998 0.02 26.27 0.24 26.54
1998–1999 0.11 20.39 3.57 24.07
Mean 1.09 15.18 3.21 19.49

References in context

The influenza attack rate varies from year to year as does the virus strain. The annual attack rate lies between 6–12% of the population. In the USA, in recent years, an annual average of approximately 36,000 people die and 200,000 people are hospitalized due to influenza. 4 x Centers for Disease Control and Prevention (CDC). Key Facts about Influenza and Influenza Vaccine. (www.cdc.gov/flu/keyfacts.htm) Based on a total population of 298 million, these figures represent mortality and hospitalization rates of 120 and 670 per million population, respectively. The current mortality rate is thus lower than the average excess mortality in the USA during the last decade ( Table 8 ). Extrapolating the current numbers for the USA, Table 9 shows the average annual excess influenza-associated deaths and hospitalizations for a number of countries in Europe.

Table 9 Estimated averages of annual excess morbidity and mortality in Europe during influenza epidemics. The numbers are extrapolated from the current USA estimates of 120 excess deaths and 670 excess hospitalizations per million population. Centers for Disease Control and Prevention (CDC). Key facts about influenza and the influenza vaccine. ( http://www.cdc.gov/flu/keyfacts.htm ) 4 x Centers for Disease Control and Prevention (CDC). Key Facts about Influenza and Influenza Vaccine. (www.cdc.gov/flu/keyfacts.htm)

Estimated averages of annual excess morbidity and mortality in Europe during influenza epidemics
Country Inhabitants (millions) Excess deaths Excess hospitalizations
France 60.5 7260 40,535
Germany 82.7 9924 55,409
Netherlands 16.3 1956 10,921
Spain 43.1 5172 28,877
Greece 11.1 1332 7437
Italy 58.1 6972 38,927
UK 59.7 7164 39,999
Sweden 9.0 1080 6030
Ukraine 46.5 5580 31,155
Poland 38.5 4620 25,795

References in context

  • The influenza attack rate varies from year to year as does the virus strain.
    Go to context

Population groups at higher risk

As discussed in the previous chapter, complications arising from influenza are more frequent and serious among adults with chronic conditions, such as pneumonia or respiratory disease, cardiac disease or cerebrovascular disease. 5 x KL Nichol, J Wuorenma, T von Sternberg. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Arch Intern Med 158 (1998) (1769 - 1776) Crossref. Influenza may cause secondary bacterial pneumonia and exacerbations of underlying chronic medical conditions that can result in hospitalization or even death. These groups are at a higher morbidity and mortality risk from influenza.

Death rates associated with influenza and pneumonia have been estimated as two per 100,000 for patients with no high-risk conditions, 10 per 100,000 in those with one high-risk condition and 377 per 100,000 in those with two or more high-risk conditions. 6 x R Zimmerman. Lowering the age for routine influenza vaccination to 50 years. Am Fam Physician 60 (1999) (2061 - 2066) Other studies have reported that influenza-related death rates are as high as 50 times greater in patients with cardiovascular disease, 100 times greater in patients with pulmonary disease, and even higher in those with two or more co-morbid conditions, than in healthy adults. 7 x WH Barker, JP Mullooly. A study of excess mortality during influenza epidemics in the United States, 1968–1976. Am J Epidemiol 115 (1982) (479 - 480)

Age poses an additional risk factor. Even in the absence of underlying medical conditions, the elderly are at increased risk for serious complications and possibly death due to influenza, primarily as a result of a decline in cell-mediated immunity with age, as discussed in Chapters 4 and 5 . Furthermore, the incidence of chronic medical conditions increases with age, adding to the risk. It is for these reasons that fatalities due to influenza rise with age and are highest among elderly people with chronic medical conditions – indeed, in this group up to 90% of influenza-related deaths are observed.

Children are also at increased risk for complications due to influenza, in particular small infants because of their immature immune system (see Chapter 5 ). As with the elderly, a chronic underlying medical condition adds to the risk. Thus, among children, the largest high-risk group involves those with asthma, accounting for approximately 7% of all children. These children have considerably more outpatient visits, antibiotic courses and higher hospitalization rates during all seasons than other children at increased risk. 8 x KM Neuzil, PF Wright, EF Mitchel, MR Griffin. The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr 137 (2000) (856 - 864) Crossref. In young children, influenza may be associated with increased rates of otitis media and, even more serious, cardiorespiratory illnesses leading to hospitalization ( Table 10 ).

Table 10 Influenza-related health-care interventions among children. source: Reproduced from Neuzil KM et al . The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr 2000; 137 : 856–864 8 x KM Neuzil, PF Wright, EF Mitchel, MR Griffin. The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr 137 (2000) (856 - 864) Crossref. with permission from Elsevier.

Influenza-related health-care interventions among children
Excess number per 1000 children
Hospitalizations for children:
  • <1 year of age
19
  • 1 to ≤ 3 years of age
8
  • Outpatient visits
200
  • Courses of antibiotic therapy
140

References in context

  • As with the elderly, a chronic underlying medical condition adds to the risk.
    Go to context

 
x

Table 8 Estimated annual influenza deaths rates per 100,000 in the USA (1990–1999). source: Reproduced from Thompson WW et al . Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA ; 289 : 179–186 3 x WW Thompson, DK Shay, E Weintraub, et al.. Mortality associated with influenza and respiratory syncytial virus in the United States. J Am Med Assoc 289 (2003) (179 - 186) Crossref. with permission from the American Medical Association.

Estimated annual influenza deaths rates per 100,000 in the USA (1990–1999)
Season A/H1N1 A/H3N2 B Total
1990–1991 0.79 2.41 7.00 10.20
1991–1992 2.57 18.11 0.22 20.90
1992–1993 0.46 7.75 7.42 15.64
1993–1994 0.07 18.88 0.16 19.10
1994–1995 0.22 12.91 2.72 15.85
1995–1996 5.58 8.94 2.84 17.36
1996–1997 0.00 20.98 4.73 25.71
1997–1998 0.02 26.27 0.24 26.54
1998–1999 0.11 20.39 3.57 24.07
Mean 1.09 15.18 3.21 19.49

References in context

Table 9 Estimated averages of annual excess morbidity and mortality in Europe during influenza epidemics. The numbers are extrapolated from the current USA estimates of 120 excess deaths and 670 excess hospitalizations per million population. Centers for Disease Control and Prevention (CDC). Key facts about influenza and the influenza vaccine. ( http://www.cdc.gov/flu/keyfacts.htm ) 4 x Centers for Disease Control and Prevention (CDC). Key Facts about Influenza and Influenza Vaccine. (www.cdc.gov/flu/keyfacts.htm)

Estimated averages of annual excess morbidity and mortality in Europe during influenza epidemics
Country Inhabitants (millions) Excess deaths Excess hospitalizations
France 60.5 7260 40,535
Germany 82.7 9924 55,409
Netherlands 16.3 1956 10,921
Spain 43.1 5172 28,877
Greece 11.1 1332 7437
Italy 58.1 6972 38,927
UK 59.7 7164 39,999
Sweden 9.0 1080 6030
Ukraine 46.5 5580 31,155
Poland 38.5 4620 25,795

References in context

  • The influenza attack rate varies from year to year as does the virus strain.
    Go to context

Table 10 Influenza-related health-care interventions among children. source: Reproduced from Neuzil KM et al . The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr 2000; 137 : 856–864 8 x KM Neuzil, PF Wright, EF Mitchel, MR Griffin. The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr 137 (2000) (856 - 864) Crossref. with permission from Elsevier.

Influenza-related health-care interventions among children
Excess number per 1000 children
Hospitalizations for children:
  • <1 year of age
19
  • 1 to ≤ 3 years of age
8
  • Outpatient visits
200
  • Courses of antibiotic therapy
140

References in context

  • As with the elderly, a chronic underlying medical condition adds to the risk.
    Go to context

References

Label Authors Title Source Year
3

References in context

WW Thompson, DK Shay, E Weintraub, et al.. Mortality associated with influenza and respiratory syncytial virus in the United States. Crossref. J Am Med Assoc 289 (2003) (179 - 186) 2003
4

References in context

  • Estimated averages of annual excess morbidity and mortality in Europe during influenza epidemics.
    Go to context

  • The influenza attack rate varies from year to year as does the virus strain.
    Go to context

Centers for Disease Control and Prevention (CDC). Key Facts about Influenza and Influenza Vaccine. (www.cdc.gov/flu/keyfacts.htm)
5

References in context

  • Influenza may cause secondary bacterial pneumonia and exacerbations of underlying chronic medical conditions that can result in hospitalization or even death.
    Go to context

KL Nichol, J Wuorenma, T von Sternberg. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Crossref. Arch Intern Med 158 (1998) (1769 - 1776) 1998
6

References in context

R Zimmerman. Lowering the age for routine influenza vaccination to 50 years. Am Fam Physician 60 (1999) (2061 - 2066) 1999
7

References in context

WH Barker, JP Mullooly. A study of excess mortality during influenza epidemics in the United States, 1968–1976. Am J Epidemiol 115 (1982) (479 - 480) 1982
8

References in context

KM Neuzil, PF Wright, EF Mitchel, MR Griffin. The burden of influenza illness in children with asthma and other chronic medical conditions. Crossref. J Pediatr 137 (2000) (856 - 864) 2000

« Back to Resource Center