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Cited by 601Influenza Virus Research StudiesVaccine Coverage and HesitancyRespiratory viral infections research

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

Jefferson, T, Rivetti, D, Rivetti, A, Rudin, M, Di Pietrantonj, C, Demicheli, V·2005·The Lancet
DOI 10.1016/s0140-6736(05)67339-4
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Abstract

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.

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  • Frailty is linked to weaker antibody responses to influenza and pneumococcal vaccines, which may explain why vaccination benefits older people only modestly.

    “Furthermore, frailty is associated with an impaired antibody response to influenza (63) and pneumococcal vaccine (64), which helps explain the observation that vaccination in older people is associated with only relatively modest clinical effectiveness (65).”

    From Frailty in elderly people (2013) · cites this paper as [65]

  • Vaccination of older individuals is only partially successful; generating new immune memory and boosting existing memory are less efficient than in childhood.

    “Attempts to improve immune competence through vaccination programs of older individuals have been only partially successful; generating immune memory to new antigens and boosting existing memory are less efficient than in childhood”

    From Successful and Maladaptive T Cell Aging (2017) · cites this paper as Jefferson et al., 2005

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Authors
Jefferson, T., Rivetti, D., Rivetti, A., Rudin, M., Di Pietrantonj, C., & Demicheli, V
ORCID
Jefferson, T
Venue
The Lancet
Publisher
Elsevier BV
Published
2005-10
Volume
366
Issue
9492
Pages
1165-1174
ISSN
  • 0099-5355 (ISSN-L)
  • 0140-6736
DOI
10.1016/s0140-6736(05)67339-4
OpenAlex
W2098832466
Cited by
601
References
87
Citations by year
2026: 7 · 2025: 16 · 2024: 12 · 2023: 12 · 2022: 15 · 2021: 17 · 2020: 23 · 2019: 17 · 2018: 18 · 2017: 19 · 2016: 18 · 2015: 22 · 2014: 30 · 2013: 48 · 2012: 43
FWCI
7.08
Type
journal article
Language
en
Open access
closed
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • The Lancet (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Epidemiology › Influenza Virus Research Studies
  • Social Sciences › Health › Vaccine Coverage and Hesitancy
  • Health Sciences › Medicine › Epidemiology › Respiratory viral infections research
Keywords
influenza vaccination, older adults, vaccine efficacy, vaccine effectiveness, influenza-like illness, pneumonia, hospitalization, all-cause mortality, long-term care facilities, community-dwelling older adults, vaccine matching, influenza complications, heart disease, respiratory diseases, influenza vaccination campaign, influenza vaccine safety
MeSH terms
Aged, Humans, Influenza, Human, Influenza Vaccines, Treatment Outcome, Drug Resistance, Viral

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