1 Department of Infectious Disease Epidemiology, Immunization Unit, Robert Koch Institute, Berlin, Germany.
2 Center for International Health Protection, Robert Koch Institute, Berlin, Germany.
3 Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Friedrich Alexander Universität (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany.
4 Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany.
5 Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.