Influenza has been identified as a trigger for an elevated risk of myocardial infarction (6-10x), stroke (3-8x) and HF hospitalization (5% increase) within 1 week of influenza-like illness. Plausible biological mechanisms for this association are now emerging. Influenza vaccination may prevent cardiovascular events. This has considerable clinical and health policy importance given the profound underuse of vaccination and the potential impact which influenza vaccination may have on high-risk patients.