Four RCTs of moderate quality conducted between 1994-2008 met inclusion criteria. In total, 3,227 patients were enrolled; 796 were early post-acute coronary syndrome, 851 had stable CVD, and 1,580 were without established CVD. A total of 187 MACE events, including 65 CV deaths, and 70 total deaths occurred after a median of 1 year of follow-up. Influenza vaccine significantly reduced the 1-year risk of MACE (M-H OR 0.52, 95% CI 0.37-0.74; p=0.0002) with a directionally consistent trend for CV death (M-H OR 0.58, 95% CI 0.25-1.36; p=0.21) and all-cause mortality (M-H OR 0.63, 95% CI 0.29-1.35; p=0.23; Figure 1
). There was no significant heterogeneity between studies (p>0.10).