1 Section of Paediatric Infectious Disease, Faculty of Medicine, Imperial College London, London, W2 1NY, UK; Centre for Paediatrics and Child Health, Imperial College London, London, W2 1NY, UK. Electronic address: m.kaforou@imperial.ac.uk.
2 Section of Paediatric Infectious Disease, Faculty of Medicine, Imperial College London, London, W2 1NY, UK; Centre for Paediatrics and Child Health, Imperial College London, London, W2 1NY, UK.
3 Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Sanquin Blood Supply, Amsterdam University Medical Center, Amsterdam, Netherlands; Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam Amsterdam University Medical Center, Amsterdam, Netherlands.
4 Department of Laboratory Medicine, Laboratory of Medical Immunology, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.