1 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
2 Dr Victor Babes Clinical Hospital of Infectious and Tropical Diseases, Bucharest, Romania.
3 Aarhus University Hospital, Skejby, Denmark.
4 Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark.
5 Center of Excellence for Health, Immunity and Infections, Copenhagen University Hospital, Rigshospitalet, Denmark.
6 WHO Collaborating Centre for Travellers' Health, Institute for Epidemiology, Biostatistics and Prevention, University of Zürich Centre for Travel Medicine, MilMedBiol Competence Centre, University of Zürich, Switzerland.