1. Department of Pediatrics; Charité University Berlin; Berlin Germany
2. National Reference Centre for Influenza; Robert Koch Institute; Berlin Germany
3. Capital Institute of Pediatrics; Beijing China
4. Department of Mathematics and Computer Sciences; Freie Universität Berlin; Berlin Germany
5. Vienna Vaccine Safety Initiative; Berlin Germany
6. University of Nottingham School of Medicine; Nottingham UK
7. Université Bourgogne Franche-Comte; Besançon France