CRP values were available from 18 children (median 8.4 mg/dl, IQR 3.9-23.1). Laboratory-confirmed co-infections were reported in a total of 13 (65%) children (4 viral, 7 bacterial, 2 fungal; Table 1 ). Diagnostic analysis for simultaneous respiratory syncytial virus (RSV) infection was performed in 10 (50%) children; in 4 with positive results. All 4 children diagnosed with both influenza and RSV suffered from pneumonia and/or bronchitis/bronchiolitis and needed PICU treatment for a median of 9 days (IQR 4-13); three were < 1 year of age. Microbiological diagnostics were performed from blood cultures of 17 (85%) patients ( Table 1 ). Other positive results were mainly reported from tracheal aspirates in patients receiving intratracheal ventilation (Table 1) . Of seven patients with bacterial co-infections, three were infected with two different bacterial species. Patients with co-infection by bacteria or fungi were treated at the PICU for a median of 18 days (IQR 12-30), and, thus, twice as long compared to patients without such co-infections (median 9 days, IQR 5-11; p = 0.01).