Cardiovascular disease related to influenza infection and the protective role of influenza vaccination

Influenza infection is a well-established trigger of severe respiratory and cardiovascular complications, particularly in older adults, frail individuals, and patients with underlying cardiovascular disease. Seasonal peaks are consistently associated with excess hospitalizations and mortality. Epidemiological studies have shown sharp increases in acute cardiac events during and immediately after influenza infection, including a high-rate of acute coronary syndromes and heart failure. The cardiovascular impact of influenza is mediated by multiple mechanisms. Systemic inflammation, plaque destabilization, metabolic imbalance, endothelial dysfunction, and pro-thrombotic activation collectively contribute to acute coronary syndromes, myocarditis, arrhythmias, and acute or worsening heart failure. These complications generate a substantial clinical and socioeconomic burden, particularly in elderly and high-risk individuals. Despite the availability of effective and inexpensive vaccines, influenza vaccination remains underused in high-risk cardiovascular populations. Randomized trials and meta-analyses consistently support vaccination as a powerful preventive tool, associated with a 25-37% reduction in major adverse cardiovascular events and mortality, with benefits comparable to established cardioprotective therapies. Evidence is strongest in patients with coronary artery disease, ACS, diabetes, and in older adults, although results in heart failure populations remain more heterogeneous. Enhanced vaccines including adjuvanted, high-dose, and cell-based formulations offer superior protection in elderly and immunocompromised individuals and are increasingly recommended by national and international health authorities. Given the robust evidence linking influenza to cardiovascular events and the proven protective role of vaccination, systematic implementation of tailored influenza immunization strategies in patients with CVD is essential to optimize preventive care.