1. Department of Maternal and Child Health, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
2. Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. ICAP at Columbia University, Mailman School of Public Health, Columbia University, New York, New York, USA.
4. Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA.
5. Center for Collaboration in Health, Maputo, Mozambique.