1 Institute of Tropical Medicine, Universitätsklinikum Tübingen, Germany; Vietnamese-German Center for Medical Research, Hanoi, Viet Nam; Faculty of Medicine, Duy Tan University, Da Nang, Viet Nam. Electronic address: velavan@medizin.uni-tuebingen.de.
2 Oxford Vaccine Group, Department of Paediatrics, University of Oxford, NIHR Oxford Biomedical Research Centre, Oxford, UK.
3 Institute of Tropical Medicine, Universitätsklinikum Tübingen, Germany; Centre de Recherches Medicales de Lambarene, Gabon.