1 Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, UK.
2 Centre for Statistics in Medicine, University of Oxford, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX3 7LD, UK.
3 Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, UK; University Hospitals Birmingham, Edgbaston, Birmingham, UK; Centre for Statistics in Medicine, University of Oxford, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX3 7LD, UK; MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow G61 1QH, UK.
4 University Hospitals Birmingham, Edgbaston, Birmingham, UK.
5 MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow G61 1QH, UK.
6 Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, UK. Electronic address: p.moss@bham.ac.uk.