UCL Institute for Global Health, University College London, and MRC Centre of Epidemiology for Child Health, UCL Institute of Child Health, and UCL Department of Epidemiology and Public Health, Leonard Cheshire Disability and Inclusive Development Centre, London, United Kingdom, and College of Medicine, University of Malawi and Department of Paediatrics & Child Health, College of Medicine and Queen Elizabeth Central Hospital, Blantyre, Malawi