Valery Ridde1,2, Samiratou Ouedraogo3, Sanni Yaya4,5. 1. CEPED (IRD-Université Paris Descartes), Universités de Paris, INSERM, IRD, Paris, France valery.ridde@ird.fr. 2. ISED, UCAD, Dakar, Senegal. 3. McGill University, Montreal, Quebec, Canada. 4. School of International Development and Global Studies, University of Ottawa, Ottawa, Ontario, Canada. 5. The George Institute for Global Health, Imperial College London, London, UK.