A multi-centre, randomized, placebo controlled, trial. Participants at high-risk for vascular events from the network of INTER- CHF will be randomized to inactivated influenza vaccine or placebo and followed prospectively over three influenza seasons. 600 participants will be enrolled prior to influenza season and randomized to either influenza vaccine or saline placebo.

Cardiovascular disease is a major cause of morbidity and mortality. There is recent evidence that infection due to influenza may precipitate vascular events such as myocardial infarctions and strokes. There is some evidence that influenza vaccination may prevent such events but the data are inconclusive. The investigators propose a randomized controlled trial to assess whether influenza vaccination will prevent vascular illness. Adults with clinical heart failure will be randomized to inactivated influenza vaccine or saline placebo. This pilot study will provide needed data to establish the feasibility of a larger study.

Inclusion Criteria:

• Age ≥ 18 years and NYHA functional class II, III and IV

Exclusion Criteria:

• Anaphylactic reaction to a previous dose of TIV
• Known IgE-mediated hypersensitivity to eggs manifested as hives, swelling of the mouth and throat, difficulty in breathing, hypotension, or shock
• Guillain-Barré syndrome within eight weeks of a previous influenza vaccine
• Anaphylactic reaction to neomycin
• Patients who have had influenza vaccine in two of the three previous years