This report was commissioned by and prepared for the Global Preparedness Monitoring Board, with funding from the Bill and Melinda Gates Foundation. The opinions expressed in this publication are those of the authors. They do not purport to reflect the opinions, views or recommendations of the Global Preparedness Monitoring Board (GPMB), the Bill and Melinda Gates Foundation, the World Health Organization or the World Bank Group. The designations employed in this publication and the presentation of material therein do not imply the expression of any opinion whatsoever on the part of the GPMB, the World Health Organization or the World Bank Group concerning the legal status of any country, area or territory. The responsibility for the interpretation and use of this publication lies with the reader.