1. Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP, UK
2. Magill Department of Anaesthesia Intensive Care and Pain Management, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK
3. Department of HIV/GUM, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH, UK