1. Department of HIV/GU Medicine, King's College London School of Medicine at Guy's, King's College and St Thomas' hospitals, Weston Education Centre, 10 Cutcombe Road, London, SE5 9RJ, UK
2. Health Protection Agency London, London South Specialist Virology Centre, Bessemer Road, London, SE5 9RS, UK
3. Department of Virology and HIV/GU Medicine, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK
4. Virus Reference Department, Health Protection Agency, Centre for Infections, 61 Colindale Avenue, London, NW9 5HT, UK
5. Pharmaceuticals Division, Hofffman‐La Roche AG, Basel, Switzerland
6. Department of Virology, Royal Free Hospital and Royal Free and University College Medical School, Pond Street, London, NW3 2QG, UK