BACKGROUND: Dexamethasone and tocilizumab are used to treat severely ill COVID-19 patients admitted to intensive care units (ICUs). We explored whether combination therapy increased the risk of superinfection compared to dexamethasone alone. METHODS: This observational, retrospective study included critically ill COVID-19 adult patients admitted to our ICU because of respiratory failure. Patients received dexamethasone with (Group 1) or without (Group 2) tocilizumab. Data were collected from electronic medical files. RESULTS: A total of 246 patients were included, of whom 150 received dexamethasone and tocilizumab, while 96 received dexamethasone alone. Acute respiratory distress syndrome was evident on admission in 226 patients, 56 of whom required mechanical ventilation (MV). Superinfections, mainly respiratory, were diagnosed in 59 patients, including 34/150 (23%) in Group 1 and 25/96 (26%) in Group 2 (p = 0.32). After multivariate analysis, the factors associated with a higher risk of superinfection included hematological malignancy (hazard ratio (HR): 2.47 (1.11-5.47), p = 0.03), MV (HR: 3.74 (1.92-7.26), p = 0.0001), and a higher SAPS-II score on admission (HR: 1.03 (1.01-1.06), p = 0.006). CONCLUSION: In critically ill COVID-19 patients, the addition of tocilizumab to dexamethasone was not associated with an increased risk of superinfection.Read less <