Observational and randomized studies suggest that influenza vaccine may reduce future cardiovascular events in patients with cardiovascular disease. Beyond classical view of indirect effect, linked to the neutralisation of the virus, it is currently considered whether the vaccination may have a direct effect on inflammatory process.Atherosclerosis is known to be driven both by lipid stress and inflammation both at local and systemic level. The investigators suggest that influenza vaccination could have a positive effect on atherosclerosis by regulating plasma inflammation. The aim of this pilot study is therefore to assess the impact of influenza vaccination in patients with stable coronary artery disease on the circulating inflammatory response, in order to validate its potential immunomodulatory effect. If it is found to be beneficial, it could also constitute a future adjuvant therapeutic tool to traditional pharmacotherapy in the prevention of cardiovascular events.

A multi-center, open-label, randomized delayed-start pilot study in 2 parallel groups will be conducted: participants will be randomized as to when the influenza vaccine will be administered, according to a 1:1 ratio between influenza vaccination immediately after inclusion or at 1-month follow-up. Blood tests for plasmatic inflammation analyses will be collected at baseline and at 1 month after study inclusion.

Inclusion Criteria:

• Subjects aged ≥ 60 years.
• With documented stable coronary artery disease.
• Subjects who, in the opinion of the investigator, can comply with the protocol requirements (i.e., show up for the follow-up visit and be able to converse with study staff).
• Signature of free, written and informed consent by the patient.
• Affiliation to a French social security system.

Exclusion Criteria:

• History of serious reaction to influenza vaccine or refusal of vaccination or contraindication to vaccination.
• Participant has received the influenza vaccine within <6 months or another vaccine.
• Acute infection within <3 months or acute worsening of chronic diseases.
• Severe neurocognitive disorders (inability to give informed consent).
• Pre-existing medical conditions or medications involving the immune system (rheumatoid arthritis or other inflammatory conditions or active cancer, recent use (within the past year) of immunosuppressive or modulating agents, including oral steroids, chemotherapy, or radiation therapy) .
• Cardiovascular surgery or other interventions within 6 months preceding the study or planned during the follow-up period.
• Patient's wish or clinical situation requiring co-administration with other vaccines or any factor hindering monitoring.
• Patient under guardianship, curatorship or safeguard of justice.