Hospital length of stay (LOS) was longer in patients with bacterial etiology compared to patients with a viral etiology. For children, LOS did not significantly vary in the different groups between viral and bacterial etiologies (Tables 5, 6 and 7). Patients with a mixed infection were more frequently admitted to the intensive care unit (ICU) and mechanically ventilated compared to patients with a viral etiology (p = 0.05; p = 0.005; respectively). If children and adults were analyzed separately, the differences within the adult population were not significant; in children, more patients with a mixed infection were mechanically ventilated (p = 0.03). All-cause and RTI-associated mortality was comparable between pathogen groups.