1 Department of Paediatrics and Child Health, School of Medicine, Makerere University, Kampala, Uganda.
2 KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya; Institute of Global Health Innovation, Department of Surgery and Cancer, Imperial College London, London SW7 2AZ, UK. Electronic address: k.maitland@imperial.ac.uk.
3 Medical Research Council Clinical Trials Unit (MRC CTU), University College London, London, UK.