Objective: To investigate whether zinc supplementation could affect serum tumor necrosis factor-alpha (TNF-alpha) levels in congenital and acquired cardiac patients attending for an influenza vaccine.,Methods: 9-18 years old, voluntary children with cardiac disease were weighed, measured height and blood samples for hemoglobin level, zinc level. IgA and IgG titers of influenza A and B serotypes and TNF-alpha levels were obtained. The children were randomly assigned to 1 of 2 groups: ZV group received both zinc supplementation and influenza vaccine; V group received influenza vaccine. Serum TNF-alpha levels were measured at 28 days after the immunization.,Results: Mean (+/- SD) serum zinc level was 100 (+/- 20) mu g/dL. Cases with congenital heart disease had lower serum zinc levels than acquired ones (93 +/- 17 mu g/dL, 116 +/- 18 mu g/dL; respectively, p < 0.001). Median titers of serum TNF-alpha decreased after vaccination (78.9 pg/mL, 74.8 pg/mL; p < 0.05) but this significant change occurred only in ZV group (77.1 pg/mL, 73.4 pg/mL; p = 0.001). Vaccine associated adverse events were similar in ZV and V groups except malaise (0% in ZV and 23.8% in V group; p < 0.05). Adverse events were similar in patients with congenital and acquired heart diseases. During the previous influenza season, 77.3% had more than two episodes of upper respiratory tract infection (URTI), however, after vaccination only 13.6% had more than two episode of URTI.,Conclusion: Zinc supplementation has a beneficial effect on malaise, one of the influenza vaccine associated adverse events, and decrease serum TNF-alpha levels. (C) 2011 Elsevier GmbH. All rights reserved.