Abstract
The purpose of this review is to update the recent information regarding the role of influenza vaccination (IV) as a strategy to reduce cardiovascular (CV) events. During the last 2 years, new meta-analysis, guidelines, and two randomized controlled trials (RCTs) were published. The IAMI trial added information regarding the safety and efficacy of IV right after an acute myocardial infarction hospitalization. A significant reduction in the primary endpoint-including mortality-was observed. More recently, the influenza vaccine to prevent vascular events trial (IVVE) trial did not meet the primary CV endpoint in patients with heart failure (HF). However, a significant reduction was observed during the seasonal peaks of Influenza circulation. COVID-19 pandemic provoked recruitment difficulties in these trials, as well as an altered influenza seasonality and incidence. Further analysis of IVVE trial is needed to clarify the precise role of IV in patients with HF. A recent meta-analysis of RCTs and observational studies indicated that IV was safe and effective to reduce CV events, and it was included in the most updated guideline. Despite these benefits, and the recommendations for its prescription by scientific societies and health regulatory agencies, the vaccination rate remains below than expected globally. The correct understanding of implementation barriers, which involve doctors, patients, and their context, is essential when continuous improvement strategies are planned, in order to improve the IV rate in at-risk subjects.