• Influenza infection [ Time Frame: 6 months ] [ Designated as safety issue: No ]
• Serologic response (≥4-fold HI titer rise) to each of the 3 antigens of the trivalent vaccine of the 2006-07 campaign [Solomon Islands/3/2006(H1N1), Wisconsin/67/2005 (H3N2), and Malaysia/2506/2004 - like strains] [ Time Frame: 1 month ] [ Designated as safety issue: No ]

• Magnitude of change in the antibody titer against each of the three influenza vaccine antigens [ Time Frame: 1 month ] [ Designated as safety issue: No ]
• Protective antibody (≥1:40) titer after vaccination [ Time Frame: 1 month ] [ Designated as safety issue: No ]
• Influenza-related death [ Time Frame: 6 months ] [ Designated as safety issue: No ]

This study wishes to understand:

1. whether vaccination against influenza in coronary artery disease (myocardial infarction and stable angina) patients is as effective as it is in healthy subjects;
2. whether vaccination really decreases the episodes of influenza infection in those coronary artery disease patients who receive the vaccine than those who do not.

Influenza infection may become complicated in patients with chronic conditions, including coronary artery disease (CAD) [1]. Influenza vaccination is now recommended as part of comprehensive secondary prevention in individuals with coronary and other atherosclerotic vascular disease (evidence level: Class I, Level B) [2]. Although there is controversial evidence pro [3,4] and against [5] the efficacy of influenza vaccination in protecting CAD population against cardiovascular events, the efficacy of vaccine in actual reduction in episodes of influenza infection and its fatal complications in CAD patients has not been, to our knowledge, well studied before. Furthermore, we found no report comparing serologic response to the influenza vaccine antigens between CAD patients and healthy controls.

This study aims to identify the efficacy of influenza vaccination in CAD individuals in terms of both serologic response (as compared with healthy individuals) and clinical outcomes (as compared with CAD patients not vaccinated).

• Coronary Artery Diseases
• Myocardial Infarction
• Stable Angina

• Biological: influenza vaccine
• Biological: placebo for influenza vaccine

• Experimental: Enrolled coronary artery disease patients who are randomly assigned to receive influenza vaccine
• Placebo Comparator: Enrolled coronary artery disease patients who are randomly assigned to receive placebo of influenza vaccine
• Experimental: Enrolled healthy subjects serve as control for CAD-Exp

• Thompson WW, Shay DK, Weintraub E, Brammer L, Bridges CB, Cox NJ, Fukuda K. Influenza-associated hospitalizations in the United States. JAMA. 2004 Sep 15;292(11):1333-40.
• Smith SC Jr, Allen J, Blair SN, Bonow RO, Brass LM, Fonarow GC, Grundy SM, Hiratzka L, Jones D, Krumholz HM, Mosca L, Pasternak RC, Pearson T, Pfeffer MA, Taubert KA; AHA/ACC; National Heart, Lung, and Blood Institute. AHA/ACC guidelines for secondary prevention for patients with coronary and other atherosclerotic vascular disease: 2006 update: endorsed by the National Heart, Lung, and Blood Institute. Circulation. 2006 May 16;113(19):2363-72. No abstract available. Erratum in: Circulation. 2006 Jun 6;113(22):e847.
• Gurfinkel EP, de la Fuente RL, Mendiz O, Mautner B. Influenza vaccine pilot study in acute coronary syndromes and planned percutaneous coronary interventions: the FLU Vaccination Acute Coronary Syndromes (FLUVACS) Study. Circulation. 2002 May 7;105(18):2143-7.
• León de la Fuente R, Gurfinkel EP, Toledo D, Mautner B; Grupo de Estudio FLUVACS. [Flu vaccination in patients with acute coronary syndromes: treatment benefit in prespecified subgroups] Rev Esp Cardiol. 2003 Oct;56(10):949-54. Spanish.
• Jackson LA, Yu O, Heckbert SR, Psaty BM, Malais D, Barlow WE, Thompson WW; Vaccine Safety Datalink Study Group. Influenza vaccination is not associated with a reduction in the risk of recurrent coronary events. Am J Epidemiol. 2002 Oct 1;156(7):634-40.
• Alpert JS, Thygesen K, Antman E, Bassand JP. Myocardial infarction redefined--a consensus document of The Joint European Society of Cardiology/American College of Cardiology Committee for the redefinition of myocardial infarction. J Am Coll Cardiol. 2000 Sep;36(3):959-69. Erratum in: J Am Coll Cardiol 2001 Mar 1;37(3):973.

Inclusion Criteria:

• Coronary artery disease (CAD) group (CAD-Exp and CAD-Control):

• Patients with the diagnosis of acute, evolving or recent MI (after recovered the acute phase) as defined by:

  1. Typical rise and gradual fall (troponin) or more rapid rise and fall (CK-MB) of biochemical markers of myocardial necrosis with at least one of the following:

• Ischemic symptoms
• Development of pathologic Qwaves on the ECG
• ECG changes indicative of ischemia (ST segment elevation or depression); OR
• Coronary artery intervention (e.g., coronary angioplasty). 2. Pathologic findings of an acute MI [1]:
• Patients with stable angina pectoris (SA) and documented coronary artery stenosis (angiography).
• Healthy Control group: healthy controls, proportionally matched by gender and age with the patient group (separate control groups for MI and SA patients).

Exclusion Criteria:

• Any acute disease
• Chronic liver or kidney diseases
• Conditions accompanied by immunosuppression (like organ transplantation, HIV)
• Diagnosed malignancy
• Incubation with influenza vaccine within the past 5 years
• Any psychological disease that interferes with regular follow-up
• Congestive heart failure (Killip class IV)
• Unstable angina; AND
• Contradictions of vaccine incubation (like egg allergy).