1. Independent Consultant, Medical Epidemiologist, Geneva, Switzerland
2. ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
3. Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
4. ICREA, Barcelona 08010, Spain
5. Pediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Esplugues, Barcelona, Spain
6. Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain