1. From the Departments of Nutrition (LCM), Paediatrics and Child Health (PJI and KJN), Immunology (LSZ), and Obstetrics and Gynaecology (PZ), University of Zimbabwe, Harare, Zimbabwe; the Johns Hopkins Bloomberg School of Public Health, Department of International Health, Baltimore (LHM and JHH); the Research Institute of the Montreal General Hospital, Montreal (BJW); and the ZVITAMBO Project, Hara