aCambridge Institute of Therapeutic Immunology and Infectious Disease

bDepartment of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge

cOxford Vaccine Group, Department of Paediatrics, University of Oxford

dNIHR Oxford Biomedical Research centre, Oxford

eDepartment of Infectious Disease, Imperial College London, St Mary's Campus, London, UK

Correspondence to Malick M. Gibani, Department of Infectious Diseases, School of Medicine, Imperial College London, St Mary's Campus, Praed Street, London W2 1NY, UK. E-mail: [email protected]