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An Optimized Hemagglutination Inhibition (HI) Assay to Quantify Influenza-specific Antibody Titers
Published on: December 1, 2017
High-Dose vs Standard-Dose Influenza Vaccines in Older Adults: A Meta-Analysis
Kristoffer Grundtvig Skaarup1,2, Mats C H Lassen1,2, Kaveh Hosseini1,2,3
1Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Copenhagen, Denmark.
JAMA Network Open
|May 26, 2026
Summary
High-dose inactivated influenza vaccine (HD-IIV) offers better protection against influenza hospitalizations in older adults compared to standard-dose (SD-IIV). However, HD-IIV did not significantly reduce all-cause mortality in this population.
Area of Science:
- Gerontology
- Vaccinology
- Epidemiology
Background:
- Older adults experience diminished immune responses to standard-dose inactivated influenza vaccine (SD-IIV).
- High-dose inactivated influenza vaccine (HD-IIV) was developed to enhance immunogenicity and protection in this demographic.
- Previous studies suggest HD-IIV provides superior protection against influenza and severe outcomes.
Purpose of the Study:
- To conduct a comprehensive meta-analysis of randomized clinical trials comparing HD-IIV and SD-IIV.
- To synthesize evidence on the effectiveness of HD-IIV versus SD-IIV in preventing hospitalization and mortality in older adults.
Main Methods:
- Systematic literature search of PubMed and Embase for trials published between December 31, 2009, and September 15, 2025.
- Inclusion of randomized clinical trials comparing HD-IIV with SD-IIV in adults aged 65 years or older.
- Data extraction and risk of bias assessment by two independent reviewers, with meta-analysis using fixed-effects models.
Main Results:
- Eight trials with 605,098 participants were analyzed.
- HD-IIV significantly reduced hospitalizations for influenza, laboratory-confirmed influenza (LCI), pneumonia or influenza, cardiorespiratory disease, and all causes compared to SD-IIV.
- No significant difference in all-cause mortality was observed between HD-IIV and SD-IIV groups.
Conclusions:
- HD-IIV demonstrates enhanced effectiveness in preventing influenza-related hospitalizations and severe outcomes in older adults.
- While HD-IIV improves protection against various hospitalization events, it does not significantly impact all-cause mortality.
- Findings support informed decision-making for influenza vaccine recommendations and policies for the elderly population.
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