1. Public Health England, Porton Down, Salisbury SP4 0JG, UK.
2. The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
3. The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK.
4. Oxford Departments of Radiology and Nuclear Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 7LE, UK.
5. Quadram Institute Bioscience, Norwich Research Park, Norfolk, UK.
6. Pandemic Preparedness Centre, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LG, UK.