Influenza Vaccination and Cardiovascular Outcomes in Patients with Coronary Artery Diseases, A placebo-controlled random-ized study; IVCAD

Background/Objectives: Influenza infection is associated with cardiovascular mor-bidity and mortality, but effect of influenza vaccination on cardiovascular outcomes is not fully understood. This clinical trial aimed to investigate correlation between car-diovascular outcomes and influenza vaccine (FluVac) in coronary artery diseases (CAD) subjects. Methods: This was a randomized single blinded placebo-controlled trial. Enrolled CAD subjects received 0.5 ml of 2007-2008 trivalent FluVac (15µg he-magglutinin of each of Solomon Islands/3/2006 (H1N1), Wisconsin/67/2005 (H3N2), and Malaysia/2506/2004 (B)). Subjects were followed up at 1 month (hemagglutinin (HA) antibody titers), and at 12 months post-vaccination for evaluation of outcomes (influenza-like episodes, acute coronary syndrome (ACS), myocardial infarction (MI), coronary revascularization, and death). Results: 278 eligible CAD subjects were ran-domized to receive either FluVac (n = 137) or placebo (n = 141) of which consequently 131 and 135 subejcts completed the study. Cardiovascular deaths (3/131 [2.29%] vs. 3/135 [2.22%]) and all-cause deaths (4/131 [3.05%] vs. 4/135 [2.96%]) were similar in both groups. Adverse cardiovascular events, including ACS, MI, and coronary revas-cularization were less frequent in the vaccine group, but did not reach statistical sig-nificance. Magnitude of antibody change and serologic response (≥4-fold HI titer rise) of all three antibodies were significantly higher in the vaccine group compared to the placebo but did not correlate with cardiovascular outcomes in the FluVac group. Con-clusions: Influenza vaccine may improve cardiovascular outcomes, though this im-provement is not correlated with post-vaccination antibody titers. Despite controver-sies, Influenza vaccination is recommended in CAD population. (ClinicalTrials.gov NCT00607178)