In total, 35% of the patients suffered from bacterial co-infection, including one fatality associated with Streptococcus pneumoniae. Patients with bacterial or fungal co-infections stayed twice as long (median 18 days) at the PICU than other influenza patients, thus indicating the high influence of those co-infections on the morbidity. Staphylococcus aureus was the most frequently observed bacterial species. The data from Germany indicate a similar situation as observed on severe paediatric influenza cases (fatalities) in the USA, which showed bacterial co-infections in 34% of patients in 2007, most frequently with Staphylococcus aureus [13] .