1 Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; KEMRI-Wellcome Trust, Nairobi, Kenya. Electronic address: meghan.kumar@lshtm.ac.uk.
2 World Bank Group, Washington, DC, USA; Dartmouth University, Hanover, NH, USA.
3 Kamuzu University of Health Sciences, Blantyre, Malawi; University of Liverpool, Liverpool, UK.
4 Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.