Influenza vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly

Topic: Risk, prevention and care in population studies

Background Upper respiratory tract illnesses have been associated with an increased risk of ischemic heart disease and stroke. During two influenza seasons, we assessed the influence of vaccination against influenza on the risk of hospitalization for heart disease and stroke, hospitalization for pneumonia and influenza, and death from all causes. Methods Cohorts of community-dwelling members of three large managed-care organizations who were at least 65 years old were studied during the 1998-1999 and 1999-2000 influenza seasons. Administrative and clinical data were used to evaluate outcomes, with multivariable logistic regression to control for base-line demographic and health characteristics of the subjects. Results There were 140,055 subjects in the 1998-1999 cohort and 146,328 in the 1999-2000 cohort, of which 55.5 percent and 59.7 percent, respectively, were immunized. At base line, vaccinated subjects were on average sicker, having higher rates of most coexisting conditions, outpatient care, and prior hospitalization for pneumonia than unvaccinated subjects. Unvaccinated subjects, however, were more likely to have been given a prior diagnosis of dementia or stroke. Vaccination against influenza was associated with a reduction in the risk of hospitalization for cardiac disease (reduction of 19 percent during both seasons [P Conclusions In the elderly, vaccination against influenza is associated with reductions in the risk of hospitalization for heart disease, cerebrovascular disease, and pneumonia or influenza as well as the risk of death from all causes during influenza seasons. These findings highlight the benefits of vaccination and support efforts to increase the rates of vaccination among the elderly.

Key findings

• Background Upper respiratory tract illnesses have been associated with an increased risk of ischemic heart disease and stroke.
• Results There were 140,055 subjects in the 1998-1999 cohort and 146,328 in the 1999-2000 cohort, of which 55.5 percent and 59.7 percent, respectively, were immunized.
• Vaccination against influenza was associated with a reduction in the risk of hospitalization for cardiac disease (reduction of 19 percent during both seasons [P<0.001]), cerebrovascular disease (reduction of 16 percent during the 1998-1999 season [P<0.018] and 23 percent during the 1999-2000 season [P<0.001]), and pneumonia or influenza (reduction of 32 percent during the 1998-1999 season [P<0.001] and 29 percent during the 1999-2000 season [P<0.001]) and a reduction in the risk of death from all causes (reduction of 48 percent during the 1998-1999 season [P<0.001] and 50 percent during the 1999-2000 season [P<0.001]).
• These findings highlight the benefits of vaccination and support efforts to increase the rates of vaccination among the elderly.

Why it matters

This study found that influenza vaccination in people aged 65 and older was associated with a reduced risk of hospitalization for cardiac disease and stroke. It did not test any treatment, cure or prevention for Alzheimer's disease, though it noted that unvaccinated subjects were more likely to have a prior diagnosis of dementia or stroke.

New to this subject? Start with our plain-English guide: Getting a diagnosis →

Study details

• Participants140,055
• Evidence strengthModerate

Read the original

• DOI: 10.1056/nejmoa025028
• PubMed: 12672859
• Original source →
• Free full text: New England Journal of Medicine →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{nichol2003-12672859,
  author  = {Nichol, K. L. and Nordin, J. and Mullooly, J. and Lask, R. and Fillbrandt, K. and Iwane, M.},
  title   = {{Influenza vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly}},
  journal = {The New England journal of medicine},
  year    = {2003},
  doi     = {10.1056/nejmoa025028},
  pmid    = {12672859},
  url     = {https://doi.org/10.1056/nejmoa025028}
}

Studies this one cites

Referenced by this study and also in the alzhub library, so you can read them here.

• Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens Archives of internal medicine · 1998-09-01 · usefulness score 51/100 · Risk factors

Related studies in Getting a diagnosis

• Association of incident dementia with hospitalizations JAMA · 2012-01-01 · usefulness score 71/100
• Metabolic reduction in the posterior cingulate cortex in very early Alzheimer's disease Annals of neurology · 1997-07-01 · usefulness score 59/100
• Eligibility for shingles vaccination and hospital-coded dementia in England and Wales: a regression discontinuity analysis in England medRxiv · 2026-07-21 · usefulness score 16/100
• Cognitive Impairment After Ischemic and Hemorrhagic Stroke: A Scientific Statement From the American Heart Association/American Stroke Association Stroke · 2023-05-01 · usefulness score 66/100
• The Montreal Cognitive Assessment (MoCA) is superior to the Mini-Mental State Examination (MMSE) for the detection of vascular cognitive impairment after acute stroke Journal of the neurological sciences · 2010-12-01 · usefulness score 64/100
• National Institute of Neurological Disorders and Stroke Consensus Diagnostic Criteria for Traumatic Encephalopathy Syndrome Neurology · 2021-03-15 · usefulness score 62/100

Also tagged “delirium”

858 studies in the library carry the topic tag “delirium”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 858 tagged studies.

• Cardiovascular risk prediction in healthy older people GeroScience · 2021-11-11 · usefulness score 68/100 · Digital health tools
• Caregiving burden, stress, and health effects among family caregivers of adult cancer patients JAMA · 2012-01-01 · usefulness score 57/100 · Caregiving
• Patient-Driven Grouping Model and Home Health Use Among Traditional Medicare Beneficiaries Journal of the American Medical Directors Association · 2026-07-04 · usefulness score 42/100 · Health systems and care delivery

Similar studies

• Vaccination as a new form of cardiovascular prevention: a European Society of Cardiology clinical consensus statement 2025 · Prevention and risk
• Understanding and reducing disability in older adults following critical illness 2015 · Clinical safety
• Age-related immune alterations and cerebrovascular inflammation 2022 · Vascular contributions
• Impact of viral and bacterial burden on cognitive impairment in elderly persons with cardiovascular diseases 2003 · Cognitive tests and assessment
• Stroke, Cardiovascular Disease, and Dementia After Hospitalized TIA 2025 · Disparities
• Cardiovascular risk and memory in non-demented elderly women 2010 · Treatments

More on Getting a diagnosis

• A review that covers this ground Incident dementia and blood pressure lowering in the Hypertension in the Very Elderly Trial cognitive function assessment (HYVET-COG): a double-blind, placebo controlled trial The Lancet. Neurology · 2008-07-07 · usefulness score 76/100
• Newest in this subject The Contribution of Routinely Collected Clinical Data to Dementia Identification in Primary Care: A Cross-Sectional Study Research Square · 2026-10-28 · Preprint — not yet peer-reviewed · usefulness score 16/100
• Newest in this subject Beyond “Denial”: Understanding and Responding to Help-Refusal in Dementia Preprints.org · 2026-10-26 · Preprint — not yet peer-reviewed · usefulness score 16/100

See all studies in Getting a diagnosis →