ObjectivesThe goal of this investigation was to determine if acute influenza infection is associated with depletion of CoQ10 compared to healthy controls and to determine any associations between CoQ10 levels and illness severity and inflammatory biomarkers.Patients and MethodsWe analyzed serum CoQ10 concentrations of patients with acute influenza enrolled in a randomized clinical trial prior to study drug administration. Patients were enrolled at a single urban tertiary care center over 3 influenza seasons (December 27, 2013 to March 31, 2016). Wilcoxon rank sum test was used to compare CoQ10 levels between influenza patients and healthy controls. Correlations with inflammatory biomarkers and severity of illness were assessed using Spearman correlation coefficient.ResultsWe analyzed CoQ10 levels from 50 patients with influenza and 29 controls. Overall, patients with acute influenza had lower levels of CoQ10 (.53 μg/mL, IQR .37‐.75 vs .72, IQR .58‐.90, P = .004). Significantly more patients in the influenza group had low CoQ10 levels (<.5 μg/mL) compared to controls (48% vs 7%, P < .001). Among influenza patients, there were significant but weak correlations between CoQ10 levels and IL‐2 (r = −.30, P = .04), TNF‐alpha (r = −.35, P = .01) and VEGF (r = .38, P = .007), but no correlation with IL‐6, IL‐10, VCAM or influenza severity of illness score (all P > .05).ConclusionsWe found that CoQ10 levels were significantly lower in patients with acute influenza infection and that these levels had significant although weak correlations with several inflammatory biomarkers.