1 Centre for Academic Primary Care (CAPC), Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK farhad.shokraneh@ndm.ox.ac.uk.
2 Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
3 Infectious Diseases Data Observatory (IDDO), Oxford, UK.
4 Institute of Health Informatics, University College London, London, UK.
5 Department of Evidence Synthesis, Systematic Review Consultants LTD, Oxford, UK.