1 Médecins Sans Frontières Operational Cell Barcelona-Athens, Barcelona 08005, Spain. Electronic address: louisa.baxter@barcelona.msf.org.
2 Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.
3 Médecins Sans Frontières Canada, Toronto, ON, Canada.
4 Médecins Sans Frontières Operational Cell Barcelona-Athens, Barcelona 08005, Spain.