1. Health Systems Research Department, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
2. Department for Reproductive Health and Research, World Health Organization, Avenue Appia 20, Geneva 1211, Switzerland
3. Department of Community Medicine, University of Nigeria, Nsukka Road, Nsukka, Nigeria
4. Department of Preventive Dentistry, College of Medicine, University of Nigeria, Nsukka Road, Nsukka, Nigeria
5. Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Old Road Campus, Oxford, Headington, UK