This activity was supported by contracts between the National Academy of Sciences and the American College of Emergency Physicians; American Hospital Association; Association of State and Territorial Health Officials; Centers for Disease Control and Prevention (Contract No. 200-2011-38807, TO #30); Department of Defense (Contract No. HT0011-11-P-0186); Department of Defense, Uniformed Services University of the Health Sciences (Contract No. HT9404-12-1-0022); Department of Health and Human Services' Administration for Children and Families (Contract No. HHSP2332014001533P); Department of Health and Human Services' National Institutes of Health: National Institute of Allergy and Infectious Diseases, National Institute of Environmental Sciences, National Library of Medicine (Contract No. HHSN26300007 [Under Base 1 #HHSN263201200074I]); Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response (Contract No. HHSO100201000021P); Department of Homeland Security, Office of Health Affairs (Contract No. HSHQDC-13-J-00384 [Under Base 1 #HSHQDC-11-D-00009]); Department of Transportation's National Highway Traffic Safety Administration (Contract No. DTNH22-10-H-00287); Department of Veterans Affairs (Contract No. 101-G09041); Food and Drug Administration (Contract No. HHSF22301027T [Under Base Contract DHHS-8598]); Infectious Diseases Society of America; Martin, Blanck & Associates; Merck Research Laboratories (Contract No. APA-2014-1666); National Association of Chain Drug Stores; National Association of County and City Health Officials; National Association of Emergency Medical Technicians; Novartis Vaccines and Diagnostics, Inc.; Pharmaceutical Research and Manufacturers of America; Robert Wood Johnson Foundation; Target Corporation; and Trauma Center Association of America. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.