Impact of High-Dose Influenza Vaccine on Cardiorespiratory Outcomes in Older Adults: An Updated Systematic Review and Meta-Analysis
In brief
High-dose flu vaccine cuts serious cardiorespiratory events by 8% in older adults
Across six trials with nearly 593,000 randomizations, adults 65 and older given high-dose flu vaccine had 8% fewer serious cardiorespiratory events than those given standard-dose vaccine, along with fewer pneumonia events and heart-failure hospitalizations. The analysis found no clear difference in stroke, major cardiovascular events, or pneumonia- and flu-related hospitalizations, so the benefits appear modest and outcome-specific.
- Journal
- American journal of preventive medicine (Q1)
- Published
- 8 October 2026
- Study design
- Systematic review / meta-analysis of RCTs
- Evidence level
- Level 1, High (CEBM 1a)
- Authors
- Larissa Araújo de Lucena, Bezalel Hakkeem, Nathalia Schettino Samad, Gabriel Erzinger, Guilherme Silva Mendes Gaia, Juliana Giorgi, et al.
- PMID
- 42849859
- DOI
- 10.1016/j.amepre.2026.108598
Why clinicians should know about it
- Picked for Pulmonary and Respiratory Medicine (paper of the day, 11 October 2026): High-dose influenza vaccine reduces pneumonia events in older adults
Abstract
INTRODUCTION: Older adults face an increased risk of influenza-related complications, particularly cardiovascular (CV) events. The comparative effectiveness of high-dose inactivated influenza vaccine (HD-IIV) versus standard-dose inactivated influenza vaccine (SD-IIV) for these outcomes remains uncertain. METHODS: Databases including PubMed, Cochrane Library, and Embase were searched from inception through September 2025 for randomized controlled trials (RCTs) comparing HD-IIV with SD-IIV in adults aged ≥ 65 years. Data synthesis was performed using a random-effects model to estimate pooled risk ratios (RRs) with 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I2 statistic and Cochran's Q test. RESULTS: Six RCTs contributing 593,048 randomizations were included, with 296,754 (50.04%) allocated to HD-IIV. Participants were 53.6% female, and 46.1% had known CV disease. Follow-up ranged from 14 days to 2 years (mean 372 days). HD-IIV was associated with fewer serious cardiorespiratory events (RR 0.92; 95% CI 0.89-0.95), pneumonia events (RR 0.81; 95% CI 0.68-0.96), hospitalizations due to heart failure (HF) (RR 0.87; 95% CI 0.78-0.98), and any respiratory disease (RR 0.93; 95% CI 0.86-1.00). No differences were detected for hospitalization for pneumonia or influenza (RR 0.73; 95% CI 0.50-1.08), MACE (RR 0.94; 95% CI 0.86-1.02), stroke (RR 0.92; 95% CI 0.83-1.02), or hospitalization for coronary events (RR 0.99; 95% CI 0.87-1.12). CONCLUSION: In adults aged ≥ 65 years, HD-IIV was associated with modest reductions in serious cardiorespiratory events, pneumonia events, and HF hospitalizations compared with SD-IIV, whereas hospitalization for pneumonia/influenza and broader atherothrombotic CV endpoints did not differ.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.