Comparing higher-dose and single standard-dose influenza vaccines in preventing cardiovascular events: a meta-analysis with 68,713 patients

Introduction: This manuscript offers an in-depth comparative examination of the effectiveness of higher-dose (double standard-dose and high-dose) influenza vaccines in contrast to a single standard-dose vaccine when it comes to alleviating major cardiovascular events.

Study design: Meta-Analysis.

Methods: To conduct this study, an exhaustive search was carried out in the medical English literature using databases such as PubMed/MEDLINE, EMBASE, and the Cochrane CENTRAL until 10 April 2024. The evaluation of associations was achieved through the calculation of pooled relative risks (RRs) accompanied by their corresponding 95% confidence intervals (CIs).

Results: A meticulous analysis encompassed a comprehensive cohort of 68,713 patients. Among these participants, 34,430 individuals were randomly assigned to receive a higher-dose influenza vaccination, whereas 34,283 received the standard influenza vaccination. Contrary to initial expectations, a higher-dose influenza vaccine did not manifest elevated efficacy compared to the standard-dose vaccine in terms of mitigating major cardiovascular events. The computed pooled RR stood at 1.0, accompanied by a 95% CI ranging from 0.93 to 1.10.

Conclusion: While this systematic review and meta-analysis did not find a statistically significant advantage of higher-dose influenza vaccines over a single standard-dose vaccine in preventing major cardiovascular events, the observed trend towards risk reduction warrants continued investigation. These findings contribute to the ongoing dialogue surrounding vaccination strategies and their implications for cardiovascular outcomes.