1 Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK. Electronic address: kerry.brown@lshtm.ac.uk.
2 Department of Population Health, London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK; Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK.
3 Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
4 Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London WC1H 9SH, UK.