University Hospitals Bristol - University Hospitals Bristol and Weston NHS Foundation Trust, University of Bristol, University Hospitals Bristol, Cardiff University - Centre for Trials Research, University of Bristol - Bristol Vaccine Centre, University Hospitals Bristol, Government of the United Kingdom - Royal United Hospitals Bath NHS Foundation Trust, Government of the United Kingdom - National Health Service (NHS), Government of the United Kingdom - Royal United Hospitals Bath NHS Foundation Trust, Public Health England - National Infection Service, University of Bristol, University of Bristol, University of Bristol, University of Bristol, National Health Service, United Kingdom, University College London, University Hospitals Bristol - University Hospitals Bristol and Weston NHS Foundation Trust, University Hospitals Bristol - University Hospitals Bristol NHS Foundation Trust, Government of the United Kingdom - National Health Service (NHS), Government of the United Kingdom - National Health Service (NHS), Government of the United Kingdom - Great Western Hospitals, The Alverton Practice, University of Bristol, University of Bristol, University of Oxford - Centre for Vaccinology and Tropical Medicine, Government of the United Kingdom - National Health Service (NHS), Government of the United Kingdom - National Health Service (NHS), University of Nottingham - Division of Epidemiology and Public Health, University of Bristol - Bristol Vaccine Centre, University of Bristol and Independent