Efficacy and effectiveness of influenza vaccines in elderly people: a systematic review

BACKGROUND Influenza vaccination of elderly individuals is recommended worldwide. Our aim was to review the evidence of efficacy and effectiveness of influenza vaccines in individuals aged 65 years or older. METHODS We searched five electronic databases to December, 2004, in any language, for randomised (n=5), cohort (n=49), and case-control (n=10) studies, assessing efficacy against influenza (reduction in laboratory-confirmed cases) or effectiveness against influenza-like illness (reduction in symptomatic cases). We expressed vaccine efficacy or effectiveness as a proportion, using the formula VE=1-relative risk (RR) or VE*=1-odds ratio (OR). We analysed the following outcomes: influenza, influenza-like illness, hospital admissions, complications, and deaths. FINDINGS In homes for elderly individuals (with good vaccine match and high viral circulation) the effectiveness of vaccines against influenza-like illness was 23% (95% CI 6-36) and non-significant against influenza (RR 1.04, 0.43-2.51). Well matched vaccines prevented pneumonia (VE 46%, 30-58) and hospital admission (VE 45%, 16-64) for and deaths from influenza or pneumonia (VE 42%, 17-59), and reduced all-cause mortality (VE 60%, 23-79). In elderly individuals living in the community, vaccines were not significantly effective against influenza (RR 0.19, 0.02-2.01), influenza-like illness (RR 1.05, 0.58-1.89), or pneumonia (RR 0.88, 0.64-1.20). Well matched vaccines prevented hospital admission for influenza and pneumonia (VE 26%, 12-38) and all-cause mortality (VE 42%, 24-55). After adjustment for confounders, vaccine performance was improved for admissions to hospital for influenza or pneumonia (VE* 27%, 21-33), respiratory diseases (VE* 22%, 15-28), and cardiac disease (VE* 24%, 18-30), and for all-cause mortality (VE* 47%, 39-54). INTERPRETATION In long-term care facilities, where vaccination is most effective against complications, the aims of the vaccination campaign are fulfilled, at least in part. However, according to reliable evidence the usefulness of vaccines in the community is modest.

[1]  T. Jefferson,et al.  Influenza vaccination for healthcare workers who work with the elderly. , 2006, The Cochrane database of systematic reviews.

[2]  S. Greenland,et al.  Influenza in the elderly: report of an outbreak and a review of vaccine effectiveness reports. , 1986, Vaccine.

[3]  J. Crooks,et al.  THE FAMILY DOCTOR IN THE CONTEXT OF BRITAIN'S SOCIAL SERVICES. , 1965, Lancet.

[4]  M. Aymard,et al.  Efficacy of the antiinfluenza A vaccination during epidemics due to A/VIC/3/75 and A/Texas/1/77 viruses. , 1979, Developments in biological standardization.

[5]  Y. Deguchi,et al.  Efficacy of Influenza Vaccine in Elderly Persons in Welfare Nursing Homes: Reduction in Risks of Mortality and Morbidity During an Influenza A (H3N2) Epidemic. , 2001, The journals of gerontology. Series A, Biological sciences and medical sciences.

[6]  J. L. Montagne,et al.  Influenza vaccine and pneumonia mortality in a nursing home population. , 1986, Archives of internal medicine.

[7]  T. Jefferson,et al.  Vaccines for preventing influenza in people with asthma. , 2000, The Cochrane database of systematic reviews.

[8]  D. Dwyer,et al.  Nursing home outbreak of influenza A (H3N2): evaluation of vaccine efficacy and influenza case definitions. , 1992 .

[9]  D. Taira,et al.  Influenza Vaccination, Hospitalizations, and Costs Among Members of a Medicare Managed Care Plan , 2001, Medical care.

[10]  D. Morse,et al.  An Outbreak of Influenza A (H3N2) in a Well Immunized Nursing Home Population , 1992, Journal of the American Geriatrics Society.

[11]  J. Puig-Barberá,et al.  Reduction in hospital admissions for pneumonia in non-institutionalised elderly people as a result of influenza vaccination: a case-control study in Spain. , 1997, Journal of epidemiology and community health.

[12]  Manfred S. Green,et al.  Influenza vaccination: reduction in hospitalizations and death rates among members of "Maccabi Healthcare Services" during the 2000-2001 influenza season. , 2003, The Israel Medical Association journal : IMAJ.

[13]  K. Nichol,et al.  Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. , 1998, Archives of internal medicine.

[14]  K. Nichol,et al.  The efficacy and cost effectiveness of vaccination against influenza among elderly persons living in the community. , 1994, The New England journal of medicine.

[15]  A. Haycox,et al.  Is influenza vaccination cost effective for healthy people between ages 65 and 74 years? A randomised controlled trial. , 2004, Vaccine.

[16]  J. Hedlund,et al.  Additive preventive effect of influenza and pneumococcal vaccines in elderly persons , 2004, European Respiratory Journal.

[17]  S. Kashiwagi,et al.  A prospective, Internet-based study of the effectiveness and safety of influenza vaccination in the 2001-2002 influenza season. , 2003, Vaccine.

[18]  Trang Vu,et al.  A meta-analysis of effectiveness of influenza vaccine in persons aged 65 years and over living in the community. , 2002, Vaccine.

[19]  R. Goodman,et al.  Impact of influenza A in a nursing home. , 1982, JAMA.

[20]  A. Monto,et al.  Influenza vaccine effectiveness in preventing hospitalization among the elderly during influenza type A and type B seasons. , 1995, International journal of epidemiology.

[21]  A. Monto,et al.  Influenza vaccine effectiveness among elderly nursing home residents: a cohort study. , 2001, American journal of epidemiology.

[22]  M. Zappa,et al.  Effectiveness of influenza vaccination in the elderly in a community in Italy , 2004, European Journal of Epidemiology.

[23]  A. Kendal,et al.  Efficacy of influenza vaccine in nursing homes. Reduction in illness and complications during an influenza A (H3N2) epidemic. , 1985, JAMA.

[24]  D. Fleming,et al.  Study of the effectiveness of influenza vaccination in the elderly in the epidemic of 1989–90 using a general practice database , 1995, Epidemiology and Infection.

[25]  D. D'alessio,et al.  Failure of inactivated influenza vaccine to protect an aged population. , 1969, JAMA.

[26]  A. Mukerjee.  Spread of influenza: a study of risk factors in homes for the elderly in Wales. , 1994, Journal of epidemiology and community health.

[27]  A. Kendal,et al.  The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home. , 1988, Archives of internal medicine.

[28]  B. Stricker,et al.  Influenza vaccination in community-dwelling elderly: impact on mortality and influenza-associated morbidity. , 2003, Archives of internal medicine.

[29]  Y. Deguchi,et al.  Efficacy of influenza vaccine in the elderly in welfare nursing homes: reduction in risks of mortality and morbidity during an influenza A (H3N2) epidemic. , 2000, Journal of medical microbiology.

[30]  M. Arakawa,et al.  Two outbreaks of influenza A (H3N2) in a Japanese nursing home in the winter of 1996-1997, with differing vaccine efficacy. , 1999, The Tohoku journal of experimental medicine.

[31]  K. Nichol,et al.  Influence of high-risk medical conditions on the effectiveness of influenza vaccination among elderly members of 3 large managed-care organizations. , 2002, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[32]  D. Kaiser,et al.  Clinical effectiveness of influenza vaccination in Manitoba. , 1993, JAMA.

[33]  C. Howells,et al.  INFLUENZA VACCINATION AND MORTALITY FROM BRONCHOPNEUMONIA IN THE ELDERLY , 1975, The Lancet.

[34]  N. Laird,et al.  Meta-analysis in clinical trials. , 1986, Controlled clinical trials.

[35]  G. Meiklejohn,et al.  Unusual Outbreak of Influenza A in a Wyoming Nursing Home , 1987, Journal of the American Geriatrics Society.

[36]  R. Smyth,et al.  Vaccines for preventing influenza in people with cystic fibrosis. , 2014, The Cochrane database of systematic reviews.

[37]  J. Díez-Domingo,et al.  Effectiveness of the MF59-adjuvanted influenza vaccine in preventing emergency admissions for pneumonia in the elderly over 64 years of age. , 2004, Vaccine.

[38]  A. Birn.  Gates's grandest challenge: transcending technology as public health ideology , 2005, The Lancet.

[39]  J. Hedlund,et al.  Effects of a large-scale intervention with influenza and 23-valent pneumococcal vaccines in adults aged 65 years or older: a prospective study , 2001, The Lancet.

[40]  D. Altman,et al.  Measuring inconsistency in meta-analyses , 2003, BMJ : British Medical Journal.

[41]  G. Dinant,et al.  The Efficacy of Influenza Vaccination in Elderly Individuals: A Randomized Double-blind Placebo-Controlled Trial , 1994 .

[42]  J. Nguyen-Van-Tam,et al.  Reduction in mortality associated with influenza vaccine during 1989-90 epidemic , 1995, The Lancet.

[43]  Influenza vaccination in 2000: recommendations and vaccine use in 50 developed and rapidly developing countries. , 2003 .

[44]  S. Wallenstein,et al.  Association of influenza immunization with reduction in mortality in an elderly population. A prospective study. , 1988, Archives of internal medicine.

[45]  E. Schiff,et al.  Evaluation of monovalent influenza vaccine in a retirement community during the epidemic of 1965-66. , 1969, JAMA.

[46]  S Greenland,et al.  Quantitative methods in the review of epidemiologic literature. , 1987, Epidemiologic reviews.

[47]  M. Hornbrook,et al.  Influenza Vaccination Programs for Elderly Persons: Cost-Effectiveness in a Health Maintenance Organization , 1994, Annals of Internal Medicine.

[48]  K. Nichol,et al.  Influenza vaccine effectiveness in preventing hospitalizations and deaths in persons 65 years or older in Minnesota, New York, and Oregon: data from 3 health plans. , 2001, The Journal of infectious diseases.

[49]  B. López Hernández,et al.  [Effectiveness of anti-flu vaccine in the elderly]. , 1994, Atencion primaria.

[50]  S. Helgerson,et al.  Influenza Outbreaks in Nursing Homes: How Effective Is Influenza Vaccine in the Institutionalized Elderly? , 1990, Infection Control & Hospital Epidemiology.

[51]  S. Thompson,et al.  Quantifying heterogeneity in a meta‐analysis , 2002, Statistics in medicine.

[52]  John Mullooly,et al.  Influenza vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly. , 2003, The New England journal of medicine.

[53]  H. Oshitani,et al.  The Effectiveness of Influenza Vaccine Against Influenza A (H3N2) Virus Infections in Nursing Homes in Niigata, Japan, During the 1998-1999 and 1999-2000 Seasons , 2002, Infection Control & Hospital Epidemiology.

[54]  K. Nicholson,et al.  Effectiveness of influenza vaccine in reducing hospital admissions during the 1989–90 epidemic , 1997, Epidemiology and Infection.

[55]  V. Hammersley,et al.  Influenza A among community-dwelling elderly persons in Leicestershire during winter 1993–4; cigarette smoking as a risk factor and the efficacy of influenza vaccination , 1999, Epidemiology and Infection.

[56]  Gavira Iglesias Fj,et al.  Analysis of an influenza vaccination campaign in rural environment , 1987 .

[57]  Jennifer A. Roberts,et al.  A cohort study of the effectiveness of influenza vaccine in older people, performed using the United Kingdom general practice research database. , 2004, The Journal of infectious diseases.

[58]  E. Israel,et al.  An outbreak of influenza A in a nursing home. , 1986, American Journal of Public Health.

[59]  R. Gasparini,et al.  [Efficacy of influenza vaccination: results in a community controlled for 2 years]. , 1980, Bollettino dell'Istituto sieroterapico milanese.

[60]  A. Monto,et al.  Effectiveness of Inactivated Influenza Vaccine Among Nursing Home Residents During an Influenza Type A (H3N2) Epidemic , 1999, Journal of the American Geriatrics Society.

[61]  S. Isaacs,et al.  Outbreak of influenza A in an Ontario nursing home--January 1997. , 1997, Canada communicable disease report = Releve des maladies transmissibles au Canada.

[62]  B. Feery,et al.  Different protection rates in various groups of volunteers given subunit influenza virus vaccine in 1976. , 1979, The Journal of infectious diseases.

[63]  John Painter,et al.  Effect of handwashing on child health: a randomised controlled trial , 2005, The Lancet.

[64]  H. Sacks,et al.  The Efficacy of Influenza Vaccine in Elderly Persons , 1995, Annals of Internal Medicine.

[65]  D. Morens,et al.  Lessons from a Nursing Home Outbreak of Influenza A , 1995, Infection Control & Hospital Epidemiology.

[66]  R. Holman,et al.  Immunogenicity and efficacy of Russian live attenuated and US inactivated influenza vaccines used alone and in combination in nursing home residents. , 2000, Vaccine.

[67]  J. Arroyo,et al.  Influenza A/Philippines/2/82 outbreak in a nursing home: limitations of influenza vaccination in the aged. , 1984, American journal of infection control.

[68]  F. Ruben,et al.  Influenza in a partially immunized aged population. Effectiveness of killed Hong Kong vaccine against infection with the England strain. , 1974, JAMA.

[69]  J. Badia,et al.  Efectividad de Un Programa de Vacunacion Antigripal en Cuatro Centros de Atencion Primaria , 1991 .

[70]  G. Tannock,et al.  Age‐related responses to influenza vaccination in the Newcastle region during 1983 and 1984 , 1987, The Medical journal of Australia.

[71]  A. Monto,et al.  Influenza vaccine effectiveness in preventing hospitalization for pneumonia in the elderly. , 1992, American journal of epidemiology.

[72]  R. Wood‐Baker,et al.  Influenza vaccine for patients with chronic obstructive pulmonary disease. , 2006, The Cochrane database of systematic reviews.

[73]  E. Israel,et al.  Influenza vaccine efficacy in a Maryland nursing home. , 1988, Maryland medical journal.

[74]  J. Gwaltney,et al.  A COMPARISON OF SUBCUTANEOUS, NASAL, AND COMBINED INFLUENZA VACCINATION. II. PROTECTION AGAINST NATURAL CHALLENGE12 , 1971, American journal of epidemiology.