High-dose influenza vaccination was found to be significantly more effective than standard dose vaccination in preventing influenza, emergency room visits, and hospital admissions for adverse outcomes related to influenza, according to study results presented at IDWeek 2022, held from October 19 to 23, in Washington, DC.

Researchers conducted an updated systematic review and meta-analysis to determine the relative efficacy and effectiveness of high-dose influenza vaccines in adults aged 65 years and older. They analyzed the efficacy of high- vs standard-dose influenza vaccination for protection against laboratory-confirmed influenza-like illness, visits to the emergency department (ED), and hospital admissions due to influenza and other related illnesses.

The researchers identified 19 studies (randomized controlled trials and observational studies) spanning 11 consecutive influenza seasons from 2009 to 2020 with a pooled cohort of more than 45 million individuals who received either high- or standard-dose influenza vaccination.

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Receipt of the high-dose influenza vaccine demonstrated increased relative efficacy and effectiveness compared with the standard-dose vaccine for protection against influenza-like illness (14.3%; 95% CI, 4.2%-23.3%), hospital and ED visits (10.4%, 95% CI, 6.8%-13.9%), and influenza hospitalization (11.2%; 95% CI, 7.4%-14.8%).

In addition, the relative efficacy and effectiveness of high-dose influenza vaccination showed increased protection against hospitalizations for pneumonia (27.3%, 95% CI, 15.3-37.6%), influenza and pneumonia (13.4%; 95% CI,7.3-19.2%), and respiratory (14.3%; 95% CI, 8.5-20.0%), cardiovascular (13.1%; 95% CI, 10.5-15.7%), cardiopulmonary (17.9%; 95% CI, 15.0-20.8%), and all-cause events (8.4%; 95% CI, 5.7-11.0%) compared with standard-dose vaccination.

Subanalyses in which stratification was performed on the basis of dominant influenza strain, study design and setting, and antigenic match showed similar results.

In analyses stratified by patient age, an additional relative increase in protection conferred by high- vs standard-dose vaccination was associated with increasing age.

“Evidence over 11 consecutive influenza seasons from both randomized and observational studies suggest HD-IIV [high-dose influenza vaccination] was consistently more effective than SD-IIV [standard-dose influenza vaccination] at reducing influenza and associated serious outcomes irrespective of recipient age and characteristics of the influenza season,” the researchers concluded.

Disclosures: All authors declared affiliations with the pharmaceutical industry. Please see the reference for a full list of disclosures.


Lee JK, Lam GK, Vaisman R, et al. Efficacy and effectiveness of high-dose influenza vaccine in older adults by age and seasonal characteristics: an updated systematic review and meta-analysis. Presented at: IDWeek 2022; October 19-23; Washington, DC. Poster 102.