Vaccines and cardiovascular outcomes: lessons learned from influenza epidemics

Abstract

Cardiovascular disease (CVD) is the leading cause of death in the world and is largely preventable. An increasing amount of evidence suggests that annual influenza vaccination reduces CVD-related morbidity and mortality. Despite various clinical guidelines recommending annual influenza vaccination for the general population for influenza-like illness risk reduction, with a particular emphasis on people with CVD, vaccination rates fall consistently below the goal established by the World Health Organization. This review outlines the importance of influenza vaccination, mechanisms of cardiovascular events in influenza, summarizing the available literature on the effects of influenza vaccine in CVD and the benefits of influenza vaccine during the COVID-19 pandemic.

Influenza vaccination: Simple, safe, and effective for patients with ischaemic heart disease and heart failure

“…Influenza infection is associated with increased risk of CV events, particularly among individuals at high CV risk 2 . Multiple pathophysiological mechanisms have been proposed to explain the associated increase in CV outcomes in individuals with influenza infection, such as atherosclerotic plaque rupture and an increased risk of atherothrombosis (secondary to the release of pro‐inflammatory cytokines resulting in a pro‐thrombotic milieu, influx of inflammatory cells, plaque destabilization, and endothelial dysfunction), increased metabolic demand due to sympathetic activation (leading to tachycardia and hypoxaemia, exacerbating supply–demand mismatch), or by direct viral effect or triggering of myocarditis 3,4 …”

“…2 Multiple pathophysiological mechanisms have been proposed to explain the associated increase in CV outcomes in individuals with influenza infection, such as atherosclerotic plaque rupture and an increased risk of atherothrombosis (secondary to the release of pro-inflammatory cytokines resulting in a pro-thrombotic milieu, influx of inflammatory cells, plaque destabilization, and endothelial dysfunction), increased metabolic demand due to sympathetic activation (leading to tachycardia and hypoxaemia, exacerbating supply-demand mismatch), or by direct viral effect or triggering of myocarditis. 3,4 Influenza vaccination (IV) is widely acknowledged as the most effective way to prevent seasonal influenza, reduce disease severity, and lower the incidence of complications and deaths. 1 It is, therefore, intuitive that IV might reduce the risk of CV events in at-risk patients, although until recently randomized controlled trials (RCTs) specifically addressing this hypothesis were small and varied in quality.…”

Benefits of influenza vaccine on stroke beyond preventing infection: Paradigm change or sheer bias?

“…Subsequent observational studies, trials, and meta‐analyses—while not unanimous—have provided further supportive evidence that influenza vaccination prevents recurrent events in patients with coronary artery disease. In a meta‐analysis of eight trials ( n = 14,420 patients), influenza vaccination, compared with standard care, led to a 25% lower risk of major adverse cardiovascular events [3]. This risk reduction is comparable to that of other standard preventive therapies, such as statins and smoking cessation [3].…”

“…In a meta‐analysis of eight trials ( n = 14,420 patients), influenza vaccination, compared with standard care, led to a 25% lower risk of major adverse cardiovascular events [3]. This risk reduction is comparable to that of other standard preventive therapies, such as statins and smoking cessation [3]. By 2020, the European Society of Cardiology also endorsed influenza vaccination to prevent recurrent cardiovascular events in patients with coronary artery disease [4].…”