Comparative effectiveness of high-dose versus standard-dose influenza vaccination in community-dwelling veterans

Clin Infect Dis. 2015 Jul 15;61(2):171-6. doi: 10.1093/cid/civ261. Epub 2015 Mar 31.


Background: Influenza is a significant cause of morbidity and mortality in older adults. High-dose (HD) trivalent inactivated vaccine has increased immunogenicity in older adults compared with standard-dose (SD) vaccine. We assessed the relative effectiveness of HD influenza vaccination (vs SD influenza vaccination).

Methods: We conducted a retrospective cohort study among patients who receive primary care at Veteran Health Administration (VHA) medical centers, and who received influenza vaccine in the 2010-2011 influenza season. The primary outcome was hospitalization for influenza or pneumonia. We also conducted an analysis in subgroups defined by age.

Results: We evaluated 25 714 patients who received HD vaccine and 139 511 who received SD vaccine in 23 VHA medical centers. The rate of hospitalization for influenza or pneumonia was 0.3% in both groups in the influenza season. After accounting for patient characteristics in propensity-adjusted analyses, the risk of hospitalization for influenza or pneumonia was not significantly lower among patients receiving HD vaccine vs those receiving SD vaccine (risk ratio, 0.98; 95% confidence interval, .68-1.40). In the subgroup of patients ≥85 years of age, receiving HD (compared with SD) vaccine was associated with lower rates of hospitalization for influenza or pneumonia.

Conclusions: HD vaccine was not found to be more effective than SD vaccine in protecting against hospitalization for influenza or pneumonia; however, we found a protective effect in the oldest subgroup of patients. Additional studies are needed to evaluate the effectiveness of HD vaccine.

Keywords: comparative effectiveness research; elderly; influenza human; influenza vaccines.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • Comparative Effectiveness Research
  • Female
  • Hospitalization / statistics & numerical data
  • Humans
  • Influenza Vaccines / administration & dosage*
  • Influenza Vaccines / immunology
  • Influenza, Human / prevention & control*
  • Male
  • Pneumonia / prevention & control
  • Retrospective Studies
  • Risk
  • Seasons
  • Vaccination / mortality
  • Vaccines, Inactivated / administration & dosage
  • Vaccines, Inactivated / immunology
  • Veterans*


  • Influenza Vaccines
  • Vaccines, Inactivated