University of Oxford - Oxford Vaccine Group, University of Turku - Institute of Biomedicine, Microbiology, Virology and Immunology, University of Oxford - Centre for Vaccinology and Tropical Medicine, University of Turku, University of Turku, University of Oxford - Centre for Vaccinology and Tropical Medicine, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, Universite Libre de Bruxelles, Institut d’Hématologie et d’Oncologie Pédiatrique (iHOPe) - Centre Léon Bérard, Radboud University Nijmegen - Radboud University Medical Center, Radboud University Nijmegen - Radboud University Medical Center, affiliation not provided to SSRN, University of Turku, affiliation not provided to SSRN, National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control, University of Oxford - Department of Paediatrics and University of Turku - Institute of Biomedicine, Microbiology, Virology and Immunology