1 Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK.
2 Immunisation and Countermeasures Division, National Infection Service, London, UK.
3 Immunoassay Laboratory, National Infection Service, Porton Down, UK.
4 Sero-epidemiology Unit, Public Health England, Public Health Laboratory Manchester, Manchester Medical Microbiology Partnership, Manchester Royal Infirmary, Manchester, UK.
5 Department of Virology, Manchester Medical Microbiology Partnership, Manchester Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK.
6 The NIHR Manchester Clinical Research Facility, Manchester University NHS Foundation Trust, Manchester, UK.
7 Kellgren Centre for Rheumatology, NIHR Manchester Biomedical Research Centre, Manchester University NHS Foundation Trust, Manchester, UK.
8 Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK.
9 Immunisation and Countermeasures Division, National Infection Service, London, UK. Shamez.Ladhani@phe.gov.uk.
10 Paediatric Infectious Diseases Research Group (PIDRG), St. Georges University of London (SGUL), London, UK. Shamez.Ladhani@phe.gov.uk.
11 Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK. P.Moss@bham.ac.uk.