1. Mortimer Market Centre, Central and North West London NHS Foundation Trust, London, United Kingdom
2. Division of Infection and Immunity, University College London, London, United Kingdom
3. Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
4. Centre for Clinical Research in Infection and Sexual Health, Institute for Global Health, University College London, London, United Kingdom
5. Department of Clinical Virology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
6. Department of Population, Policy and Practice, UCL GOS Institute of Child Health, London, United Kingdom