Cardiovascular Complications of Seasonal Influenza in the Pre- and Post-COVID-19 Era: Epidemiology, Mechanisms, and Clinical Implications

Influenza has long been a well-documented contributor to cardiovascular morbidity and mortality, particularly among high-risk groups. COVID-19 has notably altered the seasonality and natural history of pandemic influenza, with broad implications for related cardiac complications. This review examines the interaction between influenza and cardiovascular illness, especially myocardial infarction, congestive heart failure, stroke, and other acute cardiac events. We review the impact of the COVID-19 pandemic on influenza transmission dynamics, public health policy, and the evolving burden of cardiovascular complications. New evidence indicates that both diseases exacerbate endothelial dysfunction, systemic inflammation, and prothrombotic states, thereby increasing cardiovascular risk. A comparative analysis of pre- and post-COVID-19 influenza-related cardiac complications clarifies evolving trends and guides future preventive strategies. In light of the recent resurgence of influenza following the relaxation of COVID-19 mitigation measures, maximizing vaccine coverage and collaborating to manage viral infections in patients with cardiovascular disease are critical. This review focuses on key research needs to understand long-term cardiac consequences and the urgent requirement for targeted public health strategies to counter viral-mediated cardiovascular threats. In the post-COVID era, integrating influenza and COVID-19 vaccination strategies into cardiovascular risk management may represent a critical opportunity to reduce virus-triggered cardiovascular morbidity and mortality.