1. Division of Virology National Institute for Biological Standards and Control, Medicine and Healthcare products Regulatory Agency Blanche Lane, South Mimms, Potters Bar Hertfordshire UK
2. Internal Medicine Research Unit, Pfizer Research and Development, Sandwich Kent UK
3. Department of Cellular Pathology Imperial College London, St. Mary's Campus, Norfolk Place London UK
4. Department of Medicine Imperial College London, St. Mary's Campus, Norfolk Place London UK