1. Infectious Diseases Unit, Vaccine Evaluation Centre, University Hospitals of Leicester NHS Trust and Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
2. Department of Health Sciences, University of Leicester, Leicester Medical School, Leicester, UK
3. Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, UK
4. Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
5. Health Protection Agency, Centre for Infections, London, UK
6. Health Economics and Decision Science (HEDS), School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
7. Department of Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK