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Vaccination: Cornerstone of Influenza Control

How may influenza control be further improved?

Improvement of vaccine use in target groups

As indicated above, vaccination rates among target populations are not in line with recommendations by WHO, 10, x The Macroepidemiology of Influenza Vaccination (MIV) Study Group. The macroepidemiology of influenza vaccination in 56 countries, 1997–2003. Vaccine 23 (2005) (5133 - 5143) 11, x World Health Organization. Influenza vaccines. Wkly Epidemiol Rec 77 (2002) (230 - 239) 36 x Resolution WHA56.19. Prevention and control of influenza pandemics and annual epidemics (Fifty-Sixth World Health Assembly, Geneva, 19–28 May 2003) (www.who.int/gb/ebwha/pdf_files/WHA56/ea56r19.pdf) despite the well-established efficacy and effectiveness of current inactivated influenza vaccines. 12, x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. 13, x KL Nichol. Efficacy/clinical effectiveness of inactivated influenza virus vaccines in adults. KG Nicholson, RG Webster, AJ Hay (Eds.) Textbook of Influenza (Blackwell Science, 1998) (358 - 372) 33, x T Heikkinen, R Booy, M Campins, et al.. Should healthy children be vaccinated against influenza? A consensus report of the Summits of Independent European Vaccination Experts. Eur J Pediatr 21 (2005) (1 - 6) 40, x AC Voordouw, MC Sturkenboom, JP Dieleman, et al.. Annual revaccination against influenza and mortality risk in community-dwelling elderly persons. J Am Med Assoc 292 (2004) (2089 - 2095) Crossref. 48, 49, 50, and 51 x TME Govaert, CTMCN Thijs, N Masurel, et al.. The efficacy of influenza vaccination in elderly individuals. A randomized double-blind placebo-controlled trial. J Am Med Assoc 272 (1994) (1661 - 1665) x KL Nichol. Influenza vaccination in the elderly. Impact on hospitalization and mortality. Drugs Aging 22 (2005) (495 - 515) Crossref. x T Vu, S Farish, M Jenkins, H Kelly. A meta-analysis of effectiveness of influenza vaccine in persons aged 65 years and over living in the community. Vaccine 20 (2002) (1831 - 1836) Crossref. x PA Gross, AW Hermogenes, HS Sachs, J Lau, RA Levandowski. The efficacy of influenza vaccine in elderly persons: a meta-analysis and review of the literature. Ann Intern Med 123 (1995) (518 - 527) Clearly, influenza vaccines are still seriously underutilized. 10 x The Macroepidemiology of Influenza Vaccination (MIV) Study Group. The macroepidemiology of influenza vaccination in 56 countries, 1997–2003. Vaccine 23 (2005) (5133 - 5143)

The underutilization of influenza vaccines is often due to perceptions related to influenza and influenza vaccination which are based on insufficient or inappropriate information. All too often influenza is viewed as a comparatively mild disease that does not pose a serious threat. At the same time, influenza vaccination is frequently considered as ineffective or even a cause of the flu. In addition, the current mode of influenza vaccine administration by injection represents a barrier for individuals with fear of needles.

To improve the vaccination coverage rates in target groups, in accordance with WHO recommendations, 10, x The Macroepidemiology of Influenza Vaccination (MIV) Study Group. The macroepidemiology of influenza vaccination in 56 countries, 1997–2003. Vaccine 23 (2005) (5133 - 5143) 11, x World Health Organization. Influenza vaccines. Wkly Epidemiol Rec 77 (2002) (230 - 239) 36 x Resolution WHA56.19. Prevention and control of influenza pandemics and annual epidemics (Fifty-Sixth World Health Assembly, Geneva, 19–28 May 2003) (www.who.int/gb/ebwha/pdf_files/WHA56/ea56r19.pdf) it is important that existing national vaccination policies are effectively implemented. National health authorities of eight different European countries have recently discussed possible ways to reach the WHO vaccine coverage rate objectives for 2010. 29 x TD Szucs, D Muller. Influenza vaccination coverage rates in five European countries – a population-based cross-sectional analysis of two consecutive influenza seasons. Vaccine 23 (2005) (5055 - 5063) Crossref. Health-care professionals play the single most important role in making this happen. Indeed, they are in the best position to educate and motivate patients to be vaccinated. Table 19 lists a number of recommendations in this respect. As indicated in Chapter 3 and further described in Chapter 9, there is a societal urgency to achieve the WHO objectives, 36 x Resolution WHA56.19. Prevention and control of influenza pandemics and annual epidemics (Fifty-Sixth World Health Assembly, Geneva, 19–28 May 2003) (www.who.int/gb/ebwha/pdf_files/WHA56/ea56r19.pdf) because this will not only ameliorate the annual burden of influenza but also contribute to a better level of pandemic preparedness.

Table 19 Possible actions by primary-care physicians to encourage vaccine uptake in target populations. source: Courtesy of Ted van Essen on behalf of the Dutch College of General Practitioners.

Possible actions by primary-care physicians to encourage vaccine uptake in target populations
  • Mark and update the records of people recommended for vaccination.
  • Send invitation letters together with information leaflets to people recommended for vaccination.
  • Organize vaccination clinics to administer vaccine to as many target subjects as possible in a time-efficient way.
  • Promote vaccination of family members of at-risk patients and health-care personnel.
  • Display appropriate information in your patients' waiting room and in your office.

References in context

  • Indeed, they are in the best position to educate and motivate patients to be vaccinated. Table 19 lists a number of recommendations in this respect.
    Go to context

Vaccination of healthy younger adults

While younger adults are generally not at risk for serious complications due to influenza, flu remains an important cause of work absenteeism, diminished work productivity and malaise interfering with off-work activities. This is why there is an increasing awareness of the potential benefits of vaccination of working adults. 12, x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. 13 x KL Nichol. Efficacy/clinical effectiveness of inactivated influenza virus vaccines in adults. KG Nicholson, RG Webster, AJ Hay (Eds.) Textbook of Influenza (Blackwell Science, 1998) (358 - 372) Several prospective clinical studies have demonstrated the efficacy of inactivated influenza vaccines among healthy younger adults. Initial trials, conducted among military recruits several decades ago, 57 x G Meiklejohn, CH Kempe, WG Thalman, et al.. Effectiveness of polyvalent influenza A vaccine during an influenza A-prime epidemic. Am J Hyg 59 (3) (1954) (241 - 248) showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus. 58 x V Demicheli, T Jefferson, D Rivetti, et al.. Prevention and early treatment of influenza in healthy adults. Vaccine 18 (2000) (957 - 1030) Crossref. A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus. 31 x DA Turner, AJ Wailoo, NJ Cooper, et al.. The cost-effectiveness of influenza vaccination of healthy adults 50–64 years of age. Vaccine 24 (2006) (1035 - 1043) Crossref. Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match. 59, x JA Wilde, JA McMillan, J Serwint, et al.. Effectiveness of influenza vaccine in health care professionals: a randomized trial. J Am Med Assoc 281 (1999) (908 - 913) Crossref. 60 x CB Bridges, WW Thompson, MI Meltzer, et al.. Effectiveness and cost-benefit of influenza vaccination of healthy working adults: a randomized controlled trial. J Am Med Assoc 284 (2000) (1655 - 1663) Crossref. Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults ( Table 20 ).

Table 20 Benefits of influenza vaccination of healthy adults and children. ILI, influenza-like illness; URI, upper respiratory illness. source: Adapted from Nichol KL. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 2003; 21: 1769–1775 12 x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. with permission from Elsevier.

Benefits of influenza vaccination of healthy adults and children
Outcome measure Reduction (%)
Healthy adults <65 years of age
Laboratory-confirmed influenza 70–90
URI/ILI (all causes) 25–34
Work loss due to URI/ILI 32–43
Physician visits due to URI/ILI 42–44
Children
Laboratory-confirmed influenza 60–90
Acute otitis media (all causes) 30–36

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

  • A common complication of influenza among young children is acute otitis media (see Chapter 5).
    Go to context

As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place. 12, x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. 13 x KL Nichol. Efficacy/clinical effectiveness of inactivated influenza virus vaccines in adults. KG Nicholson, RG Webster, AJ Hay (Eds.) Textbook of Influenza (Blackwell Science, 1998) (358 - 372) Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% ( Table 20 ). 60, x CB Bridges, WW Thompson, MI Meltzer, et al.. Effectiveness and cost-benefit of influenza vaccination of healthy working adults: a randomized controlled trial. J Am Med Assoc 284 (2000) (1655 - 1663) Crossref. 61 x KL Nichol, A Lind, KL Margolis, et al.. The effectiveness of vaccination against influenza in healthy, working adults. New Engl J Med 333 (1995) (889 - 893) Crossref. Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account. 62 x MJ Postma, P Jansema, ML van Genugten, et al.. Pharmaco-economics of vaccinating healthy working adults against influenza; reviewing the available evidence. Drugs 62 (2002) (1013 - 1024) Crossref. For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated. 63 x KL Nichol, KP Mallon, PM Mendelman. Cost benefit of influenza vaccination in healthy, working adults: an economic analysis based on the results of a clinical trial of trivalent live attenuated influenza virus vaccine. Vaccine 21 (2003) (2207 - 2217) Crossref. In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme. 64 x DS Campbell, MH Rumley. Cost-effectiveness of the influenza vaccine in a healthy, working-age population. J Occup Environ Med 5 (1997) (408 - 414) Crossref. Other, model-based, studies also indicate that vaccinating working adults would be cost-saving. 12 x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses, 62 x MJ Postma, P Jansema, ML van Genugten, et al.. Pharmaco-economics of vaccinating healthy working adults against influenza; reviewing the available evidence. Drugs 62 (2002) (1013 - 1024) Crossref. also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective. For example, a cost-utility analysis of the US Office of Technology Assessment found in 1981 that a year of healthy life gained would cost $278 per person of 25–44 years of age and only $100 for those 45–64 years old. 65 x Office of Technology Assessment. Cost-effectiveness of influenza vaccination (Congress of the United States, Washington, DC, 1981) Recent studies in Europe have also shown the cost-effectiveness of vaccinating everyone over 50 years of age compared to current age recommendations in most countries. 30, x J Chancellor. Lowering the age threshold for routine influenza vaccination to 50 years: cost-effectiveness analysis for European countries. Vaccine (2006) in press. 31 x DA Turner, AJ Wailoo, NJ Cooper, et al.. The cost-effectiveness of influenza vaccination of healthy adults 50–64 years of age. Vaccine 24 (2006) (1035 - 1043) Crossref.

Vaccination of children

In most countries, healthy toddlers and children are not included in the target groups for annual influenza immunization. However, there is increasing epidemiological evidence of the burden of disease in children 33 x T Heikkinen, R Booy, M Campins, et al.. Should healthy children be vaccinated against influenza? A consensus report of the Summits of Independent European Vaccination Experts. Eur J Pediatr 21 (2005) (1 - 6) and of vaccination effectiveness. 33, x T Heikkinen, R Booy, M Campins, et al.. Should healthy children be vaccinated against influenza? A consensus report of the Summits of Independent European Vaccination Experts. Eur J Pediatr 21 (2005) (1 - 6) 35, x YZ Ghendon, AN Kaira, GA Elshina. The effect of mass influenza immunization in children on the morbidity of the unvaccinated elderly. Epidemiol Infect 134 (2006) (71 - 78) 66 x R Jordan, M Connock, E Albon, et al.. Universal vaccination of children against influenza: Are there indirect benefits to the community? A systematic review of the evidence. Vaccine 24 (2006) (1047 - 1062) Crossref. In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities. 66, x R Jordan, M Connock, E Albon, et al.. Universal vaccination of children against influenza: Are there indirect benefits to the community? A systematic review of the evidence. Vaccine 24 (2006) (1047 - 1062) Crossref. 67 x TA Reichert, N Sugaya, DS Fedson, et al.. The Japanese experience with vaccinating schoolchildren against influenza. New Engl J Med 344 (2001) (889 - 896) Crossref. In addition, influenza among children is a significant cause of parental work loss. Furthermore, very small children may well be at increased risk for serious influenza-associated complications. For this reason, the Advisory Committee on Immunization Practices (ACIP) in the USA now recommends routine vaccination of children of 6–23 months of age. 41 x SA Harper, K Fukuda, TM Uyeki, et al.. Advisory Committee on Immunization Practices (ACIP), Centers for Disease Control and Prevention (CDC). Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 54 (RR-8) (2005) (1 - 40) A similar recommendation has been formulated recently in a consensus report by a European vaccination expert group. 33 x T Heikkinen, R Booy, M Campins, et al.. Should healthy children be vaccinated against influenza? A consensus report of the Summits of Independent European Vaccination Experts. Eur J Pediatr 21 (2005) (1 - 6)

The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68, 69, and 70 x KM Neuzil, WD Dupont, PF Wright, KM Edwards. Efficacy of inactivated and cold-adapted vaccines against influenza A infection, 1985 to 1990: the pediatric experience. Pediatr Infect Dis J 20 (2001) (733 - 740) Crossref. x KM Neuzil, KM Edwards. Influenza vaccines in children. Semin Pediatr Infect Dis 13 (2002) (174 - 181) Crossref. x Y Schonbeck, EA Sanders, AW Hoes, et al.. Rationale and design of the prevention of respiratory infections and management in children (PRIMAKid) study: a randomized controlled trial on the effectiveness and costs of combined influenza and pneumococcal vaccination in pre-school children with recurrent respiratory tract infections. Vaccine 23 (2005) (4906 - 4914) Crossref. From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children ( Table 20 ). For example, an Italian study among children 1–6 years of age showed a reduction by 67% in ILI. Other studies generally confirm this picture. 69 x KM Neuzil, KM Edwards. Influenza vaccines in children. Semin Pediatr Infect Dis 13 (2002) (174 - 181) Crossref. The comparatively modest immunogenicity of influenza vaccines among small children is probably due to their lack of pre-exposure to either influenza virus or vaccine. Therefore, for these immunologically naive children, usually a two-dose vaccination regimen is recommended. 41 x SA Harper, K Fukuda, TM Uyeki, et al.. Advisory Committee on Immunization Practices (ACIP), Centers for Disease Control and Prevention (CDC). Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 54 (RR-8) (2005) (1 - 40)

A common complication of influenza among young children is acute otitis media (see Chapter 5). There appears to be a clear-cut benefit associated with influenza vaccination in terms of reducing the incidence of otitis media. A clinical study conducted in Finland, for example, has demonstrated a reduction of 36% in overall rate of otitis media as a result of vaccination ( Table 20 ), which corresponded to an 83% reduction among children with laboratory-confirmed influenza. 71 x T Heikkinen, O Ruuskanen, M Waris, et al.. Influenza vaccination in the prevention of acute otitis media in children. Am J Dis Child 145 (1991) (445 - 448) Crossref.

Another benefit of vaccinating children relates to the associated prevention of secondary transmission among family members or others within the neighbourhood. In a study conducted in Michigan, USA, during the 1968–69 pandemic outbreak of Hong Kong flu, vaccination of school-age children resulted in three-fold lower rates of influenza-like illness than in a control community. 72 x AS Monto, FM Davenport, JA Napier, T Francis. Modification of an outbreak of influenza in Tecumseh, Michigan by vaccination of schoolchildren. J Infect Dis 122 (1970) (16 - 25) Crossref. Interestingly, a 20-year programme in Japan, involving vaccination of school-age children, has indicated that there may be a correlation between increased vaccination of children and lower excess mortality among the elderly, 67 x TA Reichert, N Sugaya, DS Fedson, et al.. The Japanese experience with vaccinating schoolchildren against influenza. New Engl J Med 344 (2001) (889 - 896) Crossref. substantiating the notion that vaccination of children reduces secondary influenza transmission. A similar observation has been made in a recent study in Russia. 35 x YZ Ghendon, AN Kaira, GA Elshina. The effect of mass influenza immunization in children on the morbidity of the unvaccinated elderly. Epidemiol Infect 134 (2006) (71 - 78) School children in some regions in the Moscow area were systematically vaccinated with a classical inactivated subunit vaccine, whereas in control areas no such vaccination strategy was installed. This 2-year study also clearly demonstrated the benefits of vaccination of children. 35 x YZ Ghendon, AN Kaira, GA Elshina. The effect of mass influenza immunization in children on the morbidity of the unvaccinated elderly. Epidemiol Infect 134 (2006) (71 - 78)

Finally, vaccination of children appears to be highly cost-effective and in many cases cost-saving. The analysis by the US Office of Technology Assessment, referred to above, 65 x Office of Technology Assessment. Cost-effectiveness of influenza vaccination (Congress of the United States, Washington, DC, 1981) indicates that vaccination of children below 3 years of age would cost US $1122 per year of healthy life gained, while vaccinating children 3–14 years of age would only cost US $853 per year of healthy life gained. More recent analyses also clearly indicate the economic benefits of vaccination of children against influenza. 73 x GM Cohen, MD Nettleman. Economic impact of influenza vaccination in preschool children. Pediatrics 106 (2000) (973 - 976) Crossref. Even at an average cost of influenza vaccine production and administration of US $20, vaccination of children is likely to be cost-saving, part of the benefit in this respect being due to a reduction in parental work loss. 12 x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref.

Towards universal flu vaccination

As we have described in this chapter and elsewhere in the book, influenza is a major cause of illness and suffering, not only for the elderly and people with underlying medical conditions, but also for healthy younger adults and children. While younger adults are generally not at risk for serious complications due to influenza, flu remains an important cause of work absenteeism, diminished work productivity and malaise interfering with non-work activities. The economic burden of disease in healthy adults, as well as the demonstrated medical and economical benefits of vaccination, justify including this segment of the population in the recommended target groups for routine immunization.

Accumulating epidemiological data of the burden of disease in young children, together with the demonstrated direct and indirect benefits of vaccination programmes for very young and school-aged children, would justify also including this segment of the population in the recommendations for routine immunization. Based on such considerations, the European Scientific Working group on Influenza (ESWI) has recently estimated that at least 30% of the total population should be annually vaccinated against influenza. 74 x European Scientific Working Group on Influenza (ESWI). Influenza vaccination for one third of the population of the European Union (EU) 25 Member States by 2010. (www.eswi.org) (2005)

 
x

Table 19 Possible actions by primary-care physicians to encourage vaccine uptake in target populations. source: Courtesy of Ted van Essen on behalf of the Dutch College of General Practitioners.

Possible actions by primary-care physicians to encourage vaccine uptake in target populations
  • Mark and update the records of people recommended for vaccination.
  • Send invitation letters together with information leaflets to people recommended for vaccination.
  • Organize vaccination clinics to administer vaccine to as many target subjects as possible in a time-efficient way.
  • Promote vaccination of family members of at-risk patients and health-care personnel.
  • Display appropriate information in your patients' waiting room and in your office.

References in context

  • Indeed, they are in the best position to educate and motivate patients to be vaccinated. Table 19 lists a number of recommendations in this respect.
    Go to context

Table 20 Benefits of influenza vaccination of healthy adults and children. ILI, influenza-like illness; URI, upper respiratory illness. source: Adapted from Nichol KL. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 2003; 21: 1769–1775 12 x KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Vaccine 21 (2003) (1769 - 1775) Crossref. with permission from Elsevier.

Benefits of influenza vaccination of healthy adults and children
Outcome measure Reduction (%)
Healthy adults <65 years of age
Laboratory-confirmed influenza 70–90
URI/ILI (all causes) 25–34
Work loss due to URI/ILI 32–43
Physician visits due to URI/ILI 42–44
Children
Laboratory-confirmed influenza 60–90
Acute otitis media (all causes) 30–36

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

  • A common complication of influenza among young children is acute otitis media (see Chapter 5).
    Go to context

References

Label Authors Title Source Year
10

References in context


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  • Vaccination results in reductions of influenza-related respiratory illness and numbers of physician visits among all age groups, and in lower hospitalization rates and deaths among the elderly and patients at risk for serious complications of influenza.12,13 Vaccination coverage among target groups has increased considerably in recent years10 as the awareness of the impact of influenza is growing and influenza has become an important issue on the public-health agenda in many countries.15,16 However, the use of available influenza vaccines is still far from optimal.
    Go to context

  • However, in recent years, influenza vaccination has become a prominent issue on the public-health agenda in an increasing number of countries.10 Many developed as well as developing countries have now adopted formal recommendations on influenza vaccination for specific target groups.
    Go to context

  • The elderly represent the primary target group.10,11 This recommendation follows the increased susceptibility of the elderly for infectious diseases in general, which may be explained, at least partly, by a gradual decline in immune competence with age, particularly at the level of T cell function (see Chapter 4).
    Go to context

  • The elderly represent the primary target group.10,11 This recommendation follows the increased susceptibility of the elderly for infectious diseases in general, which may be explained, at least partly, by a gradual decline in immune competence with age, particularly at the level of T cell function (see Chapter 4).
    Go to context

  • The elderly represent the primary target group.10,11 This recommendation follows the increased susceptibility of the elderly for infectious diseases in general, which may be explained, at least partly, by a gradual decline in immune competence with age, particularly at the level of T cell function (see Chapter 4).
    Go to context

  • The most dramatic changes in this respect have occurred in Korea, Latin America, Japan and some central and eastern European countries.10 Figure 27 presents a survey of influenza vaccine distribution in 56 developed and rapidly developing countries in 1997 and 2003.
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  • In 1994, these figures were 80% and 20%, respectively.10 This trend indicates that many countries, including developing countries, are moving towards implementation of measures for influenza prevention and control on an annual basis.
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  • Inactivated influenza vaccines have an excellent safety record.9,14 Currently, about 300 million vaccine doses are being administered annually around the globe,10 and the overall rate of adverse reactions is extremely low.
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  • To improve the vaccination coverage rates in target groups, in accordance with WHO recommendations,10,11,36 it is important that existing national vaccination policies are effectively implemented.
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The Macroepidemiology of Influenza Vaccination (MIV) Study Group. The macroepidemiology of influenza vaccination in 56 countries, 1997–2003. Vaccine 23 (2005) (5133 - 5143) 2005
11

References in context


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  • The elderly represent the primary target group.10,11 This recommendation follows the increased susceptibility of the elderly for infectious diseases in general, which may be explained, at least partly, by a gradual decline in immune competence with age, particularly at the level of T cell function (see Chapter 4).
    Go to context


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  • To improve the vaccination coverage rates in target groups, in accordance with WHO recommendations,10,11,36 it is important that existing national vaccination policies are effectively implemented.
    Go to context

World Health Organization. Influenza vaccines. Wkly Epidemiol Rec 77 (2002) (230 - 239) 2002
12

References in context


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  • Vaccination results in reductions of influenza-related respiratory illness and numbers of physician visits among all age groups, and in lower hospitalization rates and deaths among the elderly and patients at risk for serious complications of influenza.12,13 Vaccination coverage among target groups has increased considerably in recent years10 as the awareness of the impact of influenza is growing and influenza has become an important issue on the public-health agenda in many countries.15,16 However, the use of available influenza vaccines is still far from optimal.
    Go to context

  • The recommendation is also based on the proven clinical efficacy and effectiveness of flu vaccination of the elderly.12 In most countries, flu vaccination is recommended for all individuals above 60 or 65 years of age.
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  • The recommendation is also based on the proven clinical efficacy and effectiveness of flu vaccination of the elderly.12 In most countries, flu vaccination is recommended for all individuals above 60 or 65 years of age.
    Go to context

  • The recommendation is also based on the proven clinical efficacy and effectiveness of flu vaccination of the elderly.12 In most countries, flu vaccination is recommended for all individuals above 60 or 65 years of age.
    Go to context

  • However, despite the increased vaccine use, recent surveys in Europe show that the coverage rates in target populations are still far from the WHO-recommended 75% in 2010.29,36 The current coverage rates range from 18% (Poland) to 67% (Spain) for the elderly and from 3% to 40% for various risk groups in younger populations.28,29,37 In the USA, only 35% of adults between the ages of 18 and 64 years who are at risk for serious complications due to influenza were being vaccinated in 2003.38 The implication of these findings is that many elderly and at-risk patients are not receiving the best possible protective treatment to prevent influenza or minimize the consequences of an influenza infection.
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  • As a result, many clinical studies have now produced consistent data showing the clear-cut benefits of influenza vaccination.12,13,33,35,40 Since the elderly comprise by far the largest target population for flu vaccination, the majority of studies evaluating the benefits of vaccination have been conducted among people in this age group; these will be discussed in more detail below.
    Go to context

  • In evaluating the outcome of influenza vaccination, a distinction is often made between vaccine efficacy per se and the clinical effectiveness of vaccination.12,13 Vaccine efficacy is defined as the reduction in the rate of laboratory-confirmed influenza among vaccinated compared to non-vaccinated individuals.
    Go to context

  • It is defined as the reduction of clinically relevant, but not necessarily influenza-specific, disease in a “real-life” situation, including all influenza-like illness (ILI), hospitalizations due to pneumonia from all causes or death from all causes.12,13,40 As this parameter includes – by definition – disease that is not caused by the influenza virus, clinical effectiveness of vaccination is generally estimated to be lower than the actual vaccine efficacy, as illustrated by the hypothetical example presented in Figure 28.13 Therefore, clinical effectiveness should not be confused for vaccine efficacy, as this may result in a substantial underestimation of the actual performance of the vaccine.
    Go to context

  • Numerous studies have convincingly demonstrated the clinical benefits of influenza vaccination in the elderly.12,13,40,48,49 For example, in a large study in the USA, spanning two influenza seasons (1998–2000) and involving 300,000 community-dwelling elderly people (≥65 years), influenza vaccination was performed in 55.5–59.7% of the population.
    Go to context

  • Economic evaluations, conducted in many different countries, have indicated that vaccination of senior citizens against influenza is always cost-effective and frequently cost-saving.12,13 For example, in a 6-year study carried out in Minnesota, USA, influenza vaccination of nursing-home residents was associated with an average net saving of $73 per person as a result of reductions in direct medical costs.12 Vaccination appears to be cost-effective or even cost-saving for both healthy senior citizens and high-risk elderly with underlying chronic medical conditions.
    Go to context

  • Economic evaluations, conducted in many different countries, have indicated that vaccination of senior citizens against influenza is always cost-effective and frequently cost-saving.12,13 For example, in a 6-year study carried out in Minnesota, USA, influenza vaccination of nursing-home residents was associated with an average net saving of $73 per person as a result of reductions in direct medical costs.12 Vaccination appears to be cost-effective or even cost-saving for both healthy senior citizens and high-risk elderly with underlying chronic medical conditions.
    Go to context


  • Go to context

  • This is why there is an increasing awareness of the potential benefits of vaccination of working adults.12,13 Several prospective clinical studies have demonstrated the efficacy of inactivated influenza vaccines among healthy younger adults.
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • Finally, vaccination of children appears to be highly cost-effective and in many cases cost-saving.
    Go to context

KL Nichol. The efficacy, effectiveness and cost-effectiveness of inactivated influenza virus vaccines. Crossref. Vaccine 21 (2003) (1769 - 1775) 2003
13

References in context


  • Go to context


  • Go to context

  • Vaccination results in reductions of influenza-related respiratory illness and numbers of physician visits among all age groups, and in lower hospitalization rates and deaths among the elderly and patients at risk for serious complications of influenza.12,13 Vaccination coverage among target groups has increased considerably in recent years10 as the awareness of the impact of influenza is growing and influenza has become an important issue on the public-health agenda in many countries.15,16 However, the use of available influenza vaccines is still far from optimal.
    Go to context

  • Table 17 presents the recommendations for influenza vaccination adopted in most countries.
    Go to context

  • As a result, many clinical studies have now produced consistent data showing the clear-cut benefits of influenza vaccination.12,13,33,35,40 Since the elderly comprise by far the largest target population for flu vaccination, the majority of studies evaluating the benefits of vaccination have been conducted among people in this age group; these will be discussed in more detail below.
    Go to context

  • In evaluating the outcome of influenza vaccination, a distinction is often made between vaccine efficacy per se and the clinical effectiveness of vaccination.12,13 Vaccine efficacy is defined as the reduction in the rate of laboratory-confirmed influenza among vaccinated compared to non-vaccinated individuals.
    Go to context

  • It is defined as the reduction of clinically relevant, but not necessarily influenza-specific, disease in a “real-life” situation, including all influenza-like illness (ILI), hospitalizations due to pneumonia from all causes or death from all causes.12,13,40 As this parameter includes – by definition – disease that is not caused by the influenza virus, clinical effectiveness of vaccination is generally estimated to be lower than the actual vaccine efficacy, as illustrated by the hypothetical example presented in Figure 28.13 Therefore, clinical effectiveness should not be confused for vaccine efficacy, as this may result in a substantial underestimation of the actual performance of the vaccine.
    Go to context

  • It is defined as the reduction of clinically relevant, but not necessarily influenza-specific, disease in a “real-life” situation, including all influenza-like illness (ILI), hospitalizations due to pneumonia from all causes or death from all causes.12,13,40 As this parameter includes – by definition – disease that is not caused by the influenza virus, clinical effectiveness of vaccination is generally estimated to be lower than the actual vaccine efficacy, as illustrated by the hypothetical example presented in Figure 28.13 Therefore, clinical effectiveness should not be confused for vaccine efficacy, as this may result in a substantial underestimation of the actual performance of the vaccine.
    Go to context

  • Numerous studies have convincingly demonstrated the clinical benefits of influenza vaccination in the elderly.12,13,40,48,49 For example, in a large study in the USA, spanning two influenza seasons (1998–2000) and involving 300,000 community-dwelling elderly people (≥65 years), influenza vaccination was performed in 55.5–59.7% of the population.
    Go to context

  • Economic evaluations, conducted in many different countries, have indicated that vaccination of senior citizens against influenza is always cost-effective and frequently cost-saving.12,13 For example, in a 6-year study carried out in Minnesota, USA, influenza vaccination of nursing-home residents was associated with an average net saving of $73 per person as a result of reductions in direct medical costs.12 Vaccination appears to be cost-effective or even cost-saving for both healthy senior citizens and high-risk elderly with underlying chronic medical conditions.
    Go to context


  • Go to context

  • This is why there is an increasing awareness of the potential benefits of vaccination of working adults.12,13 Several prospective clinical studies have demonstrated the efficacy of inactivated influenza vaccines among healthy younger adults.
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

KL Nichol. Efficacy/clinical effectiveness of inactivated influenza virus vaccines in adults. KG Nicholson, RG Webster, AJ Hay (Eds.) Textbook of Influenza (Blackwell Science, 1998) (358 - 372) 1998
29

References in context

  • This is particularly relevant because of the relatively low vaccine coverage rates in patients at risk who are younger than 65 years of age.27–29 Currently, more countries are considering lowering the age limit for vaccination recommendation.
    Go to context

  • However, despite the increased vaccine use, recent surveys in Europe show that the coverage rates in target populations are still far from the WHO-recommended 75% in 2010.29,36 The current coverage rates range from 18% (Poland) to 67% (Spain) for the elderly and from 3% to 40% for various risk groups in younger populations.28,29,37 In the USA, only 35% of adults between the ages of 18 and 64 years who are at risk for serious complications due to influenza were being vaccinated in 2003.38 The implication of these findings is that many elderly and at-risk patients are not receiving the best possible protective treatment to prevent influenza or minimize the consequences of an influenza infection.
    Go to context

  • However, despite the increased vaccine use, recent surveys in Europe show that the coverage rates in target populations are still far from the WHO-recommended 75% in 2010.29,36 The current coverage rates range from 18% (Poland) to 67% (Spain) for the elderly and from 3% to 40% for various risk groups in younger populations.28,29,37 In the USA, only 35% of adults between the ages of 18 and 64 years who are at risk for serious complications due to influenza were being vaccinated in 2003.38 The implication of these findings is that many elderly and at-risk patients are not receiving the best possible protective treatment to prevent influenza or minimize the consequences of an influenza infection.
    Go to context

  • Therefore, primary-care physicians and other health-care workers play a major role in implementing influenza vaccination programmes,29 as discussed in more detail in the last paragraph of this chapter.
    Go to context

  • National health authorities of eight different European countries have recently discussed possible ways to reach the WHO vaccine coverage rate objectives for 2010.29 Health-care professionals play the single most important role in making this happen.
    Go to context

TD Szucs, D Muller. Influenza vaccination coverage rates in five European countries – a population-based cross-sectional analysis of two consecutive influenza seasons. Crossref. Vaccine 23 (2005) (5055 - 5063) 2005
30

References in context

  • Table 17 presents the recommendations for influenza vaccination adopted in most countries.
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

J Chancellor. Lowering the age threshold for routine influenza vaccination to 50 years: cost-effectiveness analysis for European countries. Vaccine (2006) in press. 2006
31

References in context

  • Table 17 presents the recommendations for influenza vaccination adopted in most countries.
    Go to context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

DA Turner, AJ Wailoo, NJ Cooper, et al.. The cost-effectiveness of influenza vaccination of healthy adults 50–64 years of age. Crossref. Vaccine 24 (2006) (1035 - 1043) 2006
33

References in context

  • Table 17 presents the recommendations for influenza vaccination adopted in most countries.
    Go to context

  • As a result, many clinical studies have now produced consistent data showing the clear-cut benefits of influenza vaccination.12,13,33,35,40 Since the elderly comprise by far the largest target population for flu vaccination, the majority of studies evaluating the benefits of vaccination have been conducted among people in this age group; these will be discussed in more detail below.
    Go to context


  • Go to context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

T Heikkinen, R Booy, M Campins, et al.. Should healthy children be vaccinated against influenza? A consensus report of the Summits of Independent European Vaccination Experts. Eur J Pediatr 21 (2005) (1 - 6) 2005
35

References in context

  • Table 17 presents the recommendations for influenza vaccination adopted in most countries.
    Go to context

  • As a result, many clinical studies have now produced consistent data showing the clear-cut benefits of influenza vaccination.12,13,33,35,40 Since the elderly comprise by far the largest target population for flu vaccination, the majority of studies evaluating the benefits of vaccination have been conducted among people in this age group; these will be discussed in more detail below.
    Go to context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

  • A similar observation has been made in a recent study in Russia.35 School children in some regions in the Moscow area were systematically vaccinated with a classical inactivated subunit vaccine, whereas in control areas no such vaccination strategy was installed.
    Go to context

  • A similar observation has been made in a recent study in Russia.35 School children in some regions in the Moscow area were systematically vaccinated with a classical inactivated subunit vaccine, whereas in control areas no such vaccination strategy was installed.
    Go to context

YZ Ghendon, AN Kaira, GA Elshina. The effect of mass influenza immunization in children on the morbidity of the unvaccinated elderly. Epidemiol Infect 134 (2006) (71 - 78) 2006
36

References in context

  • However, despite the increased vaccine use, recent surveys in Europe show that the coverage rates in target populations are still far from the WHO-recommended 75% in 2010.29,36 The current coverage rates range from 18% (Poland) to 67% (Spain) for the elderly and from 3% to 40% for various risk groups in younger populations.28,29,37 In the USA, only 35% of adults between the ages of 18 and 64 years who are at risk for serious complications due to influenza were being vaccinated in 2003.38 The implication of these findings is that many elderly and at-risk patients are not receiving the best possible protective treatment to prevent influenza or minimize the consequences of an influenza infection.
    Go to context

  • However, despite the increased vaccine use, recent surveys in Europe show that the coverage rates in target populations are still far from the WHO-recommended 75% in 2010.29,36 The current coverage rates range from 18% (Poland) to 67% (Spain) for the elderly and from 3% to 40% for various risk groups in younger populations.28,29,37 In the USA, only 35% of adults between the ages of 18 and 64 years who are at risk for serious complications due to influenza were being vaccinated in 2003.38 The implication of these findings is that many elderly and at-risk patients are not receiving the best possible protective treatment to prevent influenza or minimize the consequences of an influenza infection.
    Go to context


  • Go to context

  • As indicated in Chapter 3 and further described in Chapter 9, there is a societal urgency to achieve the WHO objectives,36 because this will not only ameliorate the annual burden of influenza but also contribute to a better level of pandemic preparedness.
    Go to context

  • As indicated in Chapter 3 and further described in Chapter 9, there is a societal urgency to achieve the WHO objectives,36 because this will not only ameliorate the annual burden of influenza but also contribute to a better level of pandemic preparedness.
    Go to context

Resolution WHA56.19. Prevention and control of influenza pandemics and annual epidemics (Fifty-Sixth World Health Assembly, Geneva, 19–28 May 2003) (www.who.int/gb/ebwha/pdf_files/WHA56/ea56r19.pdf) 1928 May 2003
40

References in context

  • As a result, many clinical studies have now produced consistent data showing the clear-cut benefits of influenza vaccination.12,13,33,35,40 Since the elderly comprise by far the largest target population for flu vaccination, the majority of studies evaluating the benefits of vaccination have been conducted among people in this age group; these will be discussed in more detail below.
    Go to context

  • It is defined as the reduction of clinically relevant, but not necessarily influenza-specific, disease in a “real-life” situation, including all influenza-like illness (ILI), hospitalizations due to pneumonia from all causes or death from all causes.12,13,40 As this parameter includes – by definition – disease that is not caused by the influenza virus, clinical effectiveness of vaccination is generally estimated to be lower than the actual vaccine efficacy, as illustrated by the hypothetical example presented in Figure 28.13 Therefore, clinical effectiveness should not be confused for vaccine efficacy, as this may result in a substantial underestimation of the actual performance of the vaccine.
    Go to context

  • Numerous studies have convincingly demonstrated the clinical benefits of influenza vaccination in the elderly.12,13,40,48,49 For example, in a large study in the USA, spanning two influenza seasons (1998–2000) and involving 300,000 community-dwelling elderly people (≥65 years), influenza vaccination was performed in 55.5–59.7% of the population.
    Go to context


  • Go to context

AC Voordouw, MC Sturkenboom, JP Dieleman, et al.. Annual revaccination against influenza and mortality risk in community-dwelling elderly persons. Crossref. J Am Med Assoc 292 (2004) (2089 - 2095) 2004
41

References in context

  • The value of immunization against influenza is sometimes being questioned, as outbreaks of flu continue despite increased influenza vaccination coverage.39 Therefore, there has been a strong demand for sound scientific data on the effects of influenza vaccination.
    Go to context

  • In most countries, healthy toddlers and children are not included in the target groups for annual influenza immunization.
    Go to context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

SA Harper, K Fukuda, TM Uyeki, et al.. Advisory Committee on Immunization Practices (ACIP), Centers for Disease Control and Prevention (CDC). Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 54 (RR-8) (2005) (1 - 40) 2005
48

References in context

  • For example, in a large, randomized, double-blind, placebo-controlled trial among 1838 subjects of 60 years of age or older in the Netherlands, vaccine efficacy was found to be 58%.48 This trial was conducted in the 1991–92 winter season and involved the use of a multivalent inactivated influenza vaccine, matching well with the circulating virus.
    Go to context

  • Numerous studies have convincingly demonstrated the clinical benefits of influenza vaccination in the elderly.12,13,40,48,49 For example, in a large study in the USA, spanning two influenza seasons (1998–2000) and involving 300,000 community-dwelling elderly people (≥65 years), influenza vaccination was performed in 55.5–59.7% of the population.
    Go to context


  • Go to context

TME Govaert, CTMCN Thijs, N Masurel, et al.. The efficacy of influenza vaccination in elderly individuals. A randomized double-blind placebo-controlled trial. J Am Med Assoc 272 (1994) (1661 - 1665) 1994
49

References in context

  • Numerous studies have convincingly demonstrated the clinical benefits of influenza vaccination in the elderly.12,13,40,48,49 For example, in a large study in the USA, spanning two influenza seasons (1998–2000) and involving 300,000 community-dwelling elderly people (≥65 years), influenza vaccination was performed in 55.5–59.7% of the population.
    Go to context


  • Go to context

KL Nichol. Influenza vaccination in the elderly. Impact on hospitalization and mortality. Crossref. Drugs Aging 22 (2005) (495 - 515) 2005
50

References in context

  • A meta-analysis, including a large number of individual studies among senior citizens living in the community, concluded that vaccination significantly reduces hospitalization and death rates among the elderly (Table 18).50 Another meta-analysis has shown that influenza vaccination is also highly effective among residents of nursing homes (Table 18).51 These findings necessitate a proactive immunization practice by health-care providers in order to allow more elderly people to benefit from existing safe and efficacious influenza vaccines.
    Go to context


  • Go to context

T Vu, S Farish, M Jenkins, H Kelly. A meta-analysis of effectiveness of influenza vaccine in persons aged 65 years and over living in the community. Crossref. Vaccine 20 (2002) (1831 - 1836) 2002
51

References in context

  • A meta-analysis, including a large number of individual studies among senior citizens living in the community, concluded that vaccination significantly reduces hospitalization and death rates among the elderly (Table 18).50 Another meta-analysis has shown that influenza vaccination is also highly effective among residents of nursing homes (Table 18).51 These findings necessitate a proactive immunization practice by health-care providers in order to allow more elderly people to benefit from existing safe and efficacious influenza vaccines.
    Go to context


  • Go to context

PA Gross, AW Hermogenes, HS Sachs, J Lau, RA Levandowski. The efficacy of influenza vaccine in elderly persons: a meta-analysis and review of the literature. Ann Intern Med 123 (1995) (518 - 527) 1995
57

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

G Meiklejohn, CH Kempe, WG Thalman, et al.. Effectiveness of polyvalent influenza A vaccine during an influenza A-prime epidemic. Am J Hyg 59 (3) (1954) (241 - 248) 1954
58

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

V Demicheli, T Jefferson, D Rivetti, et al.. Prevention and early treatment of influenza in healthy adults. Crossref. Vaccine 18 (2000) (957 - 1030) 2000
59

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

JA Wilde, JA McMillan, J Serwint, et al.. Effectiveness of influenza vaccine in health care professionals: a randomized trial. Crossref. J Am Med Assoc 281 (1999) (908 - 913) 1999
60

References in context

  • Initial trials, conducted among military recruits several decades ago,57 showed that the vaccine was 70–90% efficacious in preventing laboratory-confirmed influenza, provided there was a good antigenic match between vaccine and circulating virus.58 A review of more recent clinical studies shows that the efficacy of inactivated influenza vaccines varied from 65% for all influenza seasons to 72% for those seasons where there was a good match between vaccine and circulating virus.31 Additional studies have reported vaccine efficacies in terms of prevention of confirmed influenza in the range of 80–90% in cases where there was a good match.59,60 Clearly, current inactivated influenza vaccines attain very high efficacy values among healthy younger adults (Table 20).
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

CB Bridges, WW Thompson, MI Meltzer, et al.. Effectiveness and cost-benefit of influenza vaccination of healthy working adults: a randomized controlled trial. Crossref. J Am Med Assoc 284 (2000) (1655 - 1663) 2000
61

References in context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

KL Nichol, A Lind, KL Margolis, et al.. The effectiveness of vaccination against influenza in healthy, working adults. Crossref. New Engl J Med 333 (1995) (889 - 893) 1995
62

References in context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

MJ Postma, P Jansema, ML van Genugten, et al.. Pharmaco-economics of vaccinating healthy working adults against influenza; reviewing the available evidence. Crossref. Drugs 62 (2002) (1013 - 1024) 2002
63

References in context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

KL Nichol, KP Mallon, PM Mendelman. Cost benefit of influenza vaccination in healthy, working adults: an economic analysis based on the results of a clinical trial of trivalent live attenuated influenza virus vaccine. Crossref. Vaccine 21 (2003) (2207 - 2217) 2003
64

References in context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

DS Campbell, MH Rumley. Cost-effectiveness of the influenza vaccine in a healthy, working-age population. Crossref. J Occup Environ Med 5 (1997) (408 - 414) 1997
65

References in context

  • As demonstrated by a number of studies, conducted in different countries, vaccination significantly reduces illness, absenteeism and influenza-related costs for healthy adults in the work place.12,13 Indeed, vaccination reduces upper respiratory tract and influenza-like illnesses from all causes by approximately 30%, related physician visits by >40% and work loss by >35% (Table 20).60,61 Accordingly, cost–benefit analyses, based on clinical trials or on modelling, have shown that vaccination of healthy working adults is cost-effective and in many cases cost-saving, provided that indirect costs associated with work absenteeism (see Chapter 6) are explicitly taken into account.62 For example, trials conducted in the USA have shown that – with an average cost for vaccine production and administration of $20 – the net saving would be $23 per person vaccinated.63 In another study comparing 131 vaccinated employees from six textile plants in North Carolina, USA, with 131 age- and gender-matched non-vaccinated controls from different plants, the “cost per saved lost work day” was $22.36, resulting in an overall saving of $2.58 per dollar invested in the vaccination programme.64 Other, model-based, studies also indicate that vaccinating working adults would be cost-saving.12 While recent international guidelines for pharmacoeconomic analyses do explicitly recommend the inclusion of production gains and losses,62 also when such indirect costs are not taken into account, vaccination of adults below the age of 65 turns out to be highly cost-effective.
    Go to context

  • The analysis by the US Office of Technology Assessment, referred to above,65 indicates that vaccination of children below 3 years of age would cost US $1122 per year of healthy life gained, while vaccinating children 3–14 years of age would only cost US $853 per year of healthy life gained.
    Go to context

Office of Technology Assessment. Cost-effectiveness of influenza vaccination (Congress of the United States, Washington, DC, 1981) 1981
66

References in context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

R Jordan, M Connock, E Albon, et al.. Universal vaccination of children against influenza: Are there indirect benefits to the community? A systematic review of the evidence. Crossref. Vaccine 24 (2006) (1047 - 1062) 2006
67

References in context

  • However, there is increasing epidemiological evidence of the burden of disease in children33 and of vaccination effectiveness.33,35,66 In addition to the direct benefits for the vaccinated children, a vaccination programme for children may also have the potential for reducing the impact of influenza epidemics, because children play an important role in the spread of influenza infections in communities.66,67 In addition, influenza among children is a significant cause of parental work loss.
    Go to context

  • In a study conducted in Michigan, USA, during the 1968–69 pandemic outbreak of Hong Kong flu, vaccination of school-age children resulted in three-fold lower rates of influenza-like illness than in a control community.72 Interestingly, a 20-year programme in Japan, involving vaccination of school-age children, has indicated that there may be a correlation between increased vaccination of children and lower excess mortality among the elderly,67 substantiating the notion that vaccination of children reduces secondary influenza transmission.
    Go to context

TA Reichert, N Sugaya, DS Fedson, et al.. The Japanese experience with vaccinating schoolchildren against influenza. Crossref. New Engl J Med 344 (2001) (889 - 896) 2001
68

References in context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

KM Neuzil, WD Dupont, PF Wright, KM Edwards. Efficacy of inactivated and cold-adapted vaccines against influenza A infection, 1985 to 1990: the pediatric experience. Crossref. Pediatr Infect Dis J 20 (2001) (733 - 740) 2001
69

References in context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

  • Other studies generally confirm this picture.69 The comparatively modest immunogenicity of influenza vaccines among small children is probably due to their lack of pre-exposure to either influenza virus or vaccine.
    Go to context

KM Neuzil, KM Edwards. Influenza vaccines in children. Crossref. Semin Pediatr Infect Dis 13 (2002) (174 - 181) 2002
70

References in context

  • The efficacy of influenza vaccination among children has been evaluated in a number of randomized, controlled trials, involving the use of either trivalent inactivated or experimental live-attenuated vaccines.68–70 From these studies, it appears that vaccination is highly efficacious in terms of preventing laboratory-confirmed influenza for children in their teens (∼90%), whereas a lower efficacy is seen with younger children (Table 20).
    Go to context

Y Schonbeck, EA Sanders, AW Hoes, et al.. Rationale and design of the prevention of respiratory infections and management in children (PRIMAKid) study: a randomized controlled trial on the effectiveness and costs of combined influenza and pneumococcal vaccination in pre-school children with recurrent respiratory tract infections. Crossref. Vaccine 23 (2005) (4906 - 4914) 2005
71

References in context

  • A common complication of influenza among young children is acute otitis media (see Chapter 5).
    Go to context

T Heikkinen, O Ruuskanen, M Waris, et al.. Influenza vaccination in the prevention of acute otitis media in children. Crossref. Am J Dis Child 145 (1991) (445 - 448) 1991
72

References in context

  • In a study conducted in Michigan, USA, during the 1968–69 pandemic outbreak of Hong Kong flu, vaccination of school-age children resulted in three-fold lower rates of influenza-like illness than in a control community.72 Interestingly, a 20-year programme in Japan, involving vaccination of school-age children, has indicated that there may be a correlation between increased vaccination of children and lower excess mortality among the elderly,67 substantiating the notion that vaccination of children reduces secondary influenza transmission.
    Go to context

AS Monto, FM Davenport, JA Napier, T Francis. Modification of an outbreak of influenza in Tecumseh, Michigan by vaccination of schoolchildren. Crossref. J Infect Dis 122 (1970) (16 - 25) 1970
73

References in context

  • Finally, vaccination of children appears to be highly cost-effective and in many cases cost-saving.
    Go to context

GM Cohen, MD Nettleman. Economic impact of influenza vaccination in preschool children. Crossref. Pediatrics 106 (2000) (973 - 976) 2000
74

References in context

  • Accumulating epidemiological data of the burden of disease in young children, together with the demonstrated direct and indirect benefits of vaccination programmes for very young and school-aged children, would justify also including this segment of the population in the recommendations for routine immunization.
    Go to context

European Scientific Working Group on Influenza (ESWI). Influenza vaccination for one third of the population of the European Union (EU) 25 Member States by 2010. (www.eswi.org) (2005) 2005

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