Effect of High-Dose Trivalent vs Standard-Dose Quadrivalent Influenza Vaccine on Mortality or Cardiopulmonary Hospitalization in Patients With High-risk Cardiovascular Disease: A Randomized Clinical Trial

JAMA. 2021 Jan 5;325(1):39-49. doi: 10.1001/jama.2020.23649.


Importance: Influenza is temporally associated with cardiopulmonary morbidity and mortality among those with cardiovascular disease who may mount a less vigorous immune response to vaccination. Higher influenza vaccine dose has been associated with reduced risk of influenza illness.

Objective: To evaluate whether high-dose trivalent influenza vaccine compared with standard-dose quadrivalent influenza vaccine would reduce all-cause death or cardiopulmonary hospitalization in high-risk patients with cardiovascular disease.

Design, setting, and participants: Pragmatic multicenter, double-blind, active comparator randomized clinical trial conducted in 5260 participants vaccinated for up to 3 influenza seasons in 157 sites in the US and Canada between September 21, 2016, and January 31, 2019. Patients with a recent acute myocardial infarction or heart failure hospitalization and at least 1 additional risk factor were eligible.

Interventions: Participants were randomly assigned to receive high-dose trivalent (n = 2630) or standard-dose quadrivalent (n = 2630) inactivated influenza vaccine and could be revaccinated for up to 3 seasons.

Main outcomes and measures: The primary outcome was the time to the composite of all-cause death or cardiopulmonary hospitalization during each enrolling season. The final date of follow-up was July 31, 2019. Vaccine-related adverse events were also assessed.

Results: Among 5260 randomized participants (mean [SD] age, 65.5 [12.6] years; 3787 [72%] men; 3289 [63%] with heart failure) over 3 influenza seasons, there were 7154 total vaccinations administered and 5226 (99.4%) participants completed the trial. In the high-dose trivalent vaccine group, there were 975 primary outcome events (883 hospitalizations for cardiovascular or pulmonary causes and 92 deaths from any cause) among 884 participants during 3577 participant-seasons (event rate, 45 per 100 patient-years), whereas in the standard-dose quadrivalent vaccine group, there were 924 primary outcome events (846 hospitalizations for cardiovascular or pulmonary causes and 78 deaths from any cause) among 837 participants during 3577 participant-seasons (event rate, 42 per 100 patient-years) (hazard ratio, 1.06 [95% CI, 0.97-1.17]; P = .21). In the high-dose vs standard-dose groups, vaccine-related adverse reactions occurred in 1449 (40.5%) vs 1229 (34.4%) participants and severe adverse reactions occurred in 55 (2.1%) vs 44 (1.7%) participants.

Conclusions and relevance: In patients with high-risk cardiovascular disease, high-dose trivalent inactivated influenza vaccine, compared with standard-dose quadrivalent inactivated influenza vaccine, did not significantly reduce all-cause mortality or cardiopulmonary hospitalizations. Influenza vaccination remains strongly recommended in this population.

Trial registration: ClinicalTrials.gov Identifier: NCT02787044.

Publication types

  • Comparative Study
  • Multicenter Study
  • Pragmatic Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Cardiovascular Diseases / epidemiology*
  • Cardiovascular Diseases / mortality
  • Double-Blind Method
  • Female
  • Heart Failure / complications
  • Hospitalization / statistics & numerical data
  • Humans
  • Influenza Vaccines / administration & dosage*
  • Influenza Vaccines / adverse effects
  • Influenza, Human / mortality
  • Influenza, Human / prevention & control*
  • Male
  • Middle Aged
  • Mortality*
  • Myocardial Infarction / complications
  • Risk Factors
  • Survival Analysis
  • Vaccines, Inactivated / administration & dosage


  • Influenza Vaccines
  • Vaccines, Inactivated

Associated data

  • ClinicalTrials.gov/NCT02787044