Retrospective analysis of clinical and virological parameters of influenza cases at four university hospitals in Germany, 2015.

We conducted a retrospective observational study at four German university hospitals of patients with laboratory-confirmed influenza in 2014/2015. Overall, a fatality rate of 8% was observed. Significantly more A(H1N1)pdm09 patients were admitted to ICU compared to those with A(H3N2). However, fatal outcome was not significantly increased among A(H1N1)pdm09 cases. Nosocomial infections were seen in 17% of cases. Systematic collection of data from hospitals will complement national influenza surveillance.