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Tabletop Exercise

Clade X

This training tabletop exercise is based on a fictional scenario. The inputs experts used for modeling the potential impact were fictional. It is a teaching and training resource for public health and government officials.

The Johns Hopkins Center for Health Security hosted the Clade X pandemic tabletop exercise on May 15, 2018, in Washington, DC. The purpose of the exercise was to illustrate high-level strategic decisions and policies that the United States and the world will need to pursue in order to prevent a pandemic or diminish its consequences should prevention fail.

About Clade X

Clade X was a day-long pandemic tabletop exercise that simulated a series of National Security Council–convened meetings of 10 US government leaders, played by individuals prominent in the fields of national security or epidemic response.

Drawing from actual events, Clade X identified important policy issues and preparedness challenges that could be solved with sufficient political will and attention. These issues were designed in a narrative to engage and educate the participants and the audience.

Lessons learned were distilled and shared broadly following the exercise.


Faced with a rapidly evolving biological threat landscape, government leaders in the United States and abroad are eager to identify long-term policy commitments that will strengthen preparedness and mitigate risk. Clade X illustrated high-level strategic decisions and policies needed to prevent a severe pandemic or diminish its consequences should prevention fail.

Similar to findings from the Center's two previous exercises, Dark Winter and Atlantic Storm, key takeaways from Clade X will educate senior leaders at the highest level of the US government, as well as members of the global policy and preparedness community and the general public. This is distinct from many other forms of tabletop exercises that test protocols or technical policies of a specific organization.

In addition, exercises like Clade X are a particularly effective way to help policymakers gain a fuller understanding of the urgent challenges they could face in a dynamic, real-world crisis.

Clade X logo


Tuesday, May 15, 2018
9 a.m. - 5 p.m.
Mandarin Oriental Hotel
Washington, DC


An invitation-only audience of nearly 150 people attended the exercise, and a livestream of the event on Facebook was available to everyone.

Exercise team

Eric Toner, MD, is the exercise team lead.

Exercise team members are Tom Inglesby, MD; Anita Cicero, JD; Randy Larsen, USAF (retired); Crystal Watson, DrPH, MPH; Gigi Kwik Gronvall, PhD; Jennifer Nuzzo, DrPH, SM; Monica Schoch-Spana, PhD; Tara Kirk Sell, PhD, MA; Amesh Adalja, MD; Caitlin Rivers, PhD, MPH; Christopher Hurtado, MHS; Diane Meyer, RN, MPH; Sanjana Ravi, MPH; Matthew Shearer, MPH; Michael Snyder, MALD; Matthew Watson; Richard E. Waldhorn, MD; Jackie Fox; Andrea Lapp; Nick Alexopulos, MBA; and Julia Cizek.

Clade X is supported by funding from the Open Philanthropy Project.


John Bellinger III

Playing the role of Secretary of State

Partner, Arnold & Porter
Former Legal Advisor to the US State Department and the National Security Council

John Bellinger III

John B. Bellinger III is a partner in the public international law and national security law practices of Arnold & Porter Kaye Scholer LLP in Washington, DC. He is also Adjunct Senior Fellow in International and National Security Law at the Council on Foreign Relations.

Mr. Bellinger served as the Legal Advisor for the US Department of State under Secretary of State Condoleezza Rice from April 2005 to January 2009. He previously managed Secretary Rice’s Senate confirmation and co-directed her State Department transition team. Mr. Bellinger represented the United States before the International Court of Justice in Mexico v. United States (Medellin) and the Iran-US Claims Tribunal and negotiated a number of treaties and international agreements, including the Third Additional Protocol to the Geneva Conventions. He received the Secretary of State’s Distinguished Service Award in 2009.

Mr. Bellinger served from 2001 to 2005 as Senior Associate Counsel to the President and Legal Advisor to the National Security Council at the White House, where he was the principal lawyer for the National Security Advisor and the NSC staff; he was in the White House Situation Room on 9-11. He previously served as Counsel for National Security Matters in the Criminal Division of the Justice Department (1997-2001), as Special Counsel to the Senate Select Committee on Intelligence (1996), and as Special Assistant to Director of Central Intelligence William Webster (1988-1991).

He is a member of the Secretary of State's Advisory Committee on International Law; one of four US Members of the Permanent Court of Arbitration in The Hague; and a member of the US "National Group," which nominates judges to the International Court of Justice. He is also a member of the Council on Foreign Relations, the Executive Council of the American Law Institute, and the Boards of Directors of the Stimson Center and the American Ditchley Foundation. Mr. Bellinger testifies regularly before Congress, has lectured at numerous US and foreign universities and law schools, and is the author of many articles and op-eds on international law issues. He is a senior contributor to the Lawfare blog.

Mr. Bellinger received his AB from Princeton University’s Woodrow Wilson School of Public and International Affairs, his JD from Harvard Law School, and an MA in foreign affairs from the University of Virginia.

Jim Talent

Playing the role of Secretary of Defense

Visiting Scholar, American Enterprise Institute
Member, Defense Policy Board
Former US Representative and Senator (R-MO)

Jim Talent

Senator Jim Talent is a national security leader who specializes in issues related to the Department of Defense. He has been active in Missouri and national public policy for over 30 years.

Senator Talent’s public service began in 1984, when at the age of 28 he was elected to the Missouri House of Representatives, where he served for 8 years. In 1992, he was elected to the first of 4 terms in the US House of Representatives, where he represented Missouri’s Second Congressional District. He was the chairman of the House Small Business Committee from 1997 to 2001. Under his leadership, the Small Business Committee became one of the most prolific and bipartisan in the House of Representatives, passing numerous bills without a single dissenting vote.

In 2002, Missourians elected Talent to serve in the United States Senate, where he served on the Armed Services, Energy and Natural Resources, and Agriculture Committees.

Talent has been fighting for a strong national defense since he entered the House of Representatives in 1993. During his first term, he spoke out on the House floor against the cuts in the size and strength of the military in the immediate aftermath of the Cold War. He continued these efforts during his years on the Senate Armed Services Committee, where he was chairman of the Naval Power Subcommittee. His last speech in the Senate in 2006 was on the need to rebuild the force, which even then was too small, too stressed, and desperately in need of recapitalization.

Since leaving the Senate in 2007, Senator Talent has worked primarily in the field of national defense issues. In 2007, he joined the Heritage Foundation as a distinguished fellow, specializing in military affairs. He is currently a visiting scholar at the American Enterprise Institute and was the director of its National Security 2020 project at the Marilyn Ware Center for Security Studies. He is also a senior fellow at the Bipartisan Policy Center.

In 2008, Talent served as vice chairman, with former Senator Bob Graham of Florida, of the Commission on Prevention of Weapons of Mass Destruction Proliferation and Terrorism, and he co-authored the Commission Report focusing on the danger of bioterrorism. He and Senator Graham subsequently reorganized the Commission as a nonprofit organization and issued a comprehensive report on the state of America’s ability to recognize and respond to a biological pandemic or attack.

Senator Talent also served on the National Defense Panel in 2010 and 2014, is a member of the US-China Economic and Security Review Commission, co-chaired a Task Force on Pentagon personnel for the Bipartisan Policy Center, and was Governor Romney’s senior advisor on defense issues during his 2012 campaign for president. He is currently a member of the Defense Policy Board, a senior advisory council to the Secretary of Defense.

Senator Talent is a regular contributor to National Review Online and appears weekly on the Hugh Hewitt show to discuss issues relating to the military and national security.

Jamie Gorelick

Playing the role of Attorney General

Partner, Wilmer/Hale
Former Deputy Attorney General

Jamie Gorelick

As one of Washington’s best-known litigators, Jamie Gorelick has represented corporations and individuals in a wide array of matters, particularly in the regulatory and enforcement arenas. Routinely listed as one of the “Best Lawyers in America,” she has been profiled as “A Legend in the Law” in the Washington Lawyer and was listed by the National Law Journal as one of the “Thirty Greatest Washington Lawyers of the Last 30 Years.”

Ms. Gorelick was one of the longest-serving Deputy Attorneys General of the United States, the second highest position in the Department of Justice. She also served as General Counsel of the Department of Defense. Earlier in her career, Ms. Gorelick was vice chair of the Task Force on the Audit, Inspection and Investigation Components of the Department of Defense. She was also Assistant to the Secretary and Counselor to the Deputy Secretary of Energy.

Ms. Gorelick has served on numerous government boards and commissions. She is currently a member of the Defense Policy Board at the US Department of Defense. Previously, Ms. Gorelick was a member of the bipartisan National Commission on Terrorist Attacks Upon the United States (the “9/11 Commission”). She was also a member of the CIA's National Security Advisory Panel, President George W. Bush’s Review of Intelligence Committee, and she co-chaired President Clinton’s Advisory Committee to the Presidential Commission on Critical Infrastructure Protection.

Ms. Gorelick is a member of the Trilateral Commission and the Council on Foreign Relations. She chairs the board of the Urban Institute.

Margaret Hamburg

Playing the role of Secretary of Health and Human Services

Foreign Secretary, National Academy of Medicine
President, AAAS
Former Commissioner, US Food & Drug Administration

Margaret Hamburg

Margaret Hamburg is an internationally recognized leader in public health and medicine. As Foreign Secretary of the National Academy of Medicine, she serves as senior advisor on international matters and liaison with other academies of medicine around the world. She is also President of the American Association for the Advancement of Science (AAAS).

Dr. Hamburg is a former Commissioner of the US Food and Drug Administration (FDA), where she was known for advancing regulatory science, modernizing regulatory pathways, and globalization of the agency. Before this, she was founding vice president and senior scientist at the Nuclear Threat Initiative, a foundation dedicated to reducing nuclear, chemical, and biological threats. Other positions have included Assistant Secretary for Planning and Evaluation (HHS), Health Commissioner for New York City, and Assistant Director of the National Institute of Allergy and Infectious Diseases.

Dr. Hamburg currently sits on the boards of the Commonwealth Fund, the Simons Foundation, the Global Alliance for Vaccines and Immunization, the Urban Institute, and the American Museum of Natural History. She serves in various advisory roles, including the Harvard University Global Advisory Council and the Scientific Advisory Committee for the Gates Foundation. Dr. Hamburg is an elected member of the Council on Foreign Relations and the National Academy of Medicine, and a Fellow of the AAAS and the American College of Physicians. She has received numerous awards and honorary degrees.

Dr. Hamburg is a graduate of Harvard College and Harvard Medical School.

Tara O’Toole

Playing the role of Secretary of Homeland Security

Executive Vice President and Senior Fellow, In-Q-Tel
Former Under Secretary for Science and Technology,
Department of Homeland Security

Tara O’Toole

Dr. Tara O’Toole is an Executive Vice President and Senior Fellow at In-Q-Tel. Prior to joining IQT, Dr. O’Toole served as Under Secretary for Science and Technology at the Department of Homeland Security. In this role, she was responsible for scientific and technological research designed to provide new security and resilience innovations. Previously, she was the CEO and Director of the Center for Biosecurity at the University of Pittsburgh Medical Center (UPMC), an independent organization dedicated to improving the country’s resilience to major biological threats. O’Toole is internationally known for her work on biosecurity and on health and safety issues related to the US nuclear weapons complex. Her publications in the biodefense field include contagious disease epidemics, biodefense research and development strategies, and hospital preparedness.

O’Toole has a bachelor’s degree from Vassar College, an MD from George Washington University, and a master’s of public health degree from Johns Hopkins University. She completed internal medicine residency training at Yale University and a fellowship in occupational and environmental medicine at Johns Hopkins University.

Jeffrey Smith

Playing the role of CIA Director

Former Head, Arnold & Porter,
National Security Practice
Former CIA General Counsel

Jeffrey Smith

Jeffrey Smith is a retired partner and former head of Arnold & Porter’s National Security practice. He regularly counseled both US and foreign companies on a wide range of national security issues. His practice included advising major defense and aerospace companies and representing major media organizations and individuals with respect to First Amendment issues and unauthorized disclosures of classified information. Mr. Smith has frequently represented prominent individuals in congressional investigations and federal prosecutions. He has also represented major universities on national security issues.

Mr. Smith is a former General Counsel of the Central Intelligence Agency (CIA). He has also served as General Counsel of the Senate Armed Services Committee and was Senator Sam Nunn's designee to the Senate Select Committee on Intelligence and the Iran/Contra Committee. Prior to working for the Senate, he was the Assistant Legal Adviser for Law Enforcement and Intelligence at the State Department. Earlier, as an Army Judge Advocate General officer, he served as the Pentagon's lawyer for the Panama Canal negotiations.

In 1992 and 1993, Mr. Smith served as the chief of the Clinton Transition Team at the US Department of Defense. He also chaired the Joint Security Commission established in 1993 by Secretary of Defense Les Aspin and CIA Director James Woolsey to examine the security procedures of the defense and intelligence communities and the companies that contract with them. In addition, he served on the congressionally mandated Commission on Roles and Missions of the Armed Services.

Tom Daschle

Playing the role of Senate Majority Leader

CEO, The Daschle Group
Former Senate Majority and Minority Leader

Tom Daschle

Tom Daschle is the founder and CEO of The Daschle Group, a public policy advisory of Baker Donelson. The Daschle Group is a full-service strategic advisory firm that advises clients on a broad array of economic, policy, and political issues.

Senator Daschle has participated in the development and debate of almost every major public policy issue of the last 3 decades. In 1978, he was elected to the US House of Representatives, where he served for 8 years. In 1986, he was elected to the US Senate and was chosen as Senate Democratic Leader in 1994. Senator Daschle is one of the longest serving Senate Democratic leaders in history and one of only 2 to serve twice as both Majority and Minority Leader.

During his tenure, Senator Daschle navigated the Senate through some of its most historic economic and national security challenges. In 2003, he chronicled some of these experiences in his book, Like No Other Time: The 107th Congress and the Two Years That Changed America Forever. In the 2013 release of The US Senate: Fundamentals of American Government, Senator Daschle explored the inner workings of this important part of the legislative branch. In his latest book, Crisis Point, Senator Daschle and former Senate Majority Leader Trent Lott explore the political gridlock in Washington and offer their vision for moving the country forward.

Since leaving the Senate, Senator Daschle has remained an active and learned voice among policymakers. As a well-known expert on health policy reform, he has written 2 books: Critical: What We Can Do About the Health-Care Crisis and Getting It Done: How Obama and Congress Finally Broke the Stalemate to Make Way for Health Care Reform.

Senator Daschle has also emerged as a leading thinker on climate change, food security, and renewable energy policy. He serves on both advisory and governing boards of a number of corporate and nonprofit organizations and currently co-chairs The Cuba Consortium, an organization dedicated to an improved relationship with the people of Cuba.

In 2007, Senator Daschle joined with former Majority Leaders George Mitchell, Bob Dole, and Howard Baker to create the Bipartisan Policy Center, an organization dedicated to finding common ground on some of the pressing public policy challenges of our time. Senator Daschle is chair of the board of directors at the Center for American Progress and vice-chair for the National Democratic Institute. He serves on the board of the Edward M. Kennedy Institute and the LBJ Foundation. He also is a member of the Health Policy and Management Executive Council at the Harvard School of Public Health and the Council of Foreign Relations.

Born in Aberdeen, South Dakota, Senator Daschle attended South Dakota State University, graduating in 1969. He then served for 3 years as an intelligence officer in the US Air Force Strategic Command. Following his military service, he spent 5 years as an aide to South Dakota Senator James Abourezk. After leaving the Senate in 2005, Senator Daschle joined Alston & Bird LLP as a special policy advisor and then went on to work in the same role at DLA Piper before establishing The Daschle Group in 2014.

Rep. Susan Brooks

Member, US House of Representatives

Current member of Congress

Rep. Susan Brooks

Congresswoman Susan W. Brooks represents the 5th District of Indiana, which spans 8 urban, suburban, and rural counties in central Indiana, including the north side of Indianapolis. She uses her background as a Deputy Mayor of Indianapolis, a US Attorney, and a community college administrator to improve education, jobs, health, and homeland security.

Congresswoman Brooks currently serves on the House Energy and Commerce Committee and is a member of the Communications and Technology, the Health, and the Oversight and Investigations Subcommittees. Through her membership on the Energy and Commerce Committee, she is working on mental health, substance abuse, and biodefense. As chairwoman of the Ethics Committee, she works with her colleagues to restore confidence in Congress.

Before joining the House of Representatives, Congresswoman Brooks received her undergraduate degree from Miami University of Ohio, then went on to pursue a juris doctor from the Indiana University Robert H. McKinney School of Law. In 2001, President George W. Bush appointed her as US Attorney for the Southern District of Indiana. In this position, she received bipartisan acclaim for her efforts to battle mortgage fraud, gun violence, drug trafficking, gangs, child exploitation, and identity theft. Prior to her election, she served as senior vice president and general counsel for Ivy Tech Community College, with a focus on statewide workforce development strategies.

Julie Gerberding

Playing the role of CDC Director

Executive Vice President and Chief Patient Officer,
Strategic Communications, Global Public Policy, and Population Health
Merck & Co., Inc.
Former CDC Director

Julie Gerberding

Dr. Julie Gerberding is Executive Vice President and Chief Patient Officer, Strategic Communications, Global Public Policy, and Population Health at Merck & Co., Inc., where she also has responsibility for the Merck for Mothers program and the Merck Foundation. As Chief Patient Officer, Dr. Gerberding leads efforts to engage with patients and patient organizations to bring their perspectives into Merck and MSD to help inform company decisions, and she represents Merck globally on patient-related matters. In addition, she is building new initiatives designed to accelerate Merck’s ability to contribute to improved population health, a measure increasingly valued by consumers, health organizations, and communities.

As a world-renowned infectious disease and public health expert, Dr. Gerberding is a leader well-versed in and passionate about acting with purpose and urgency to meet patient needs. She joined Merck in January 2010 as president of Merck Vaccines and, during her leadership of that business, helped make the company’s vaccines increasingly more available and affordable to people in emerging markets and some of the most resource-limited countries in the world. Dr. Gerberding also helped lead the successful launch in India of the MSD Wellcome Trust Hilleman Laboratories, a not-for-profit joint venture for vaccine development. In 1998, she left her tenured academic faculty appointment at the University of California, San Francisco, to lead the US Centers for Disease Control and Prevention (CDC) Division of Healthcare Quality Promotion and then served as the CDC Director from 2002 to 2009.

As director, Dr. Gerberding led the CDC through more than 40 emergency responses to public health crises, including anthrax bioterrorism, SARS, and natural disasters. She also advised governments around the world on urgent issues such as pandemic preparedness, AIDS, antimicrobial resistance, tobacco, and cancer. At the University of California, San Francisco (UCSF), Dr. Gerberding directed the Prevention Epicenter, a multidisciplinary research, training, and clinical service program that focused on the prevention of infections in patients and their healthcare providers.

Dr. Gerberding received her undergraduate and MD degrees from Case Western Reserve University (CWRU). She completed her internship and residency in internal medicine and fellowship in clinical pharmacology and infectious diseases at the University of California, San Francisco (UCSF), where she is currently an Adjunct Associate Clinical Professor of Medicine in Infectious Diseases. Dr. Gerberding received a master’s of public health degree at the University of California, Berkeley. She is a member of the Institute of Medicine and a fellow of the Infectious Diseases Society of America and the American College of Physicians, and is board certified in internal medicine and infectious diseases.

Dr. Gerberding currently serves on the boards of Cerner Corporation, CWRU, MSD Wellcome Trust Hilleman Laboratories, and the BIO Executive Committee. She has received more than 50 awards and honors, including the US Department of Health and Human Services Distinguished Service Award for her leadership in responses to anthrax bioterrorism and the September 11, 2001, attacks. She was named to Forbes Magazine’s 100 Most Powerful Women in the World from 2005 through 2008 and to TIME Magazine’s 100 Most Influential People in the World in 2004.


Executive summary

This document provides an overview of the exercise format and scenario, and concludes with recommendations from the Center on high-level strategic decisions and policies needed to prevent a severe pandemic or diminish its consequences should prevention fail.

Clade X Exercise Executive Summary Document


Policy implications

Full description of 6 strategic policy goals the Johns Hopkins Center for Health Security recommends that the United States commit to in order to prevent or reduce the catastrophic outcomes possible in future pandemics like Clade X.

Implications of Clade X for National Policy


Slide deck

Primary and supplementary slides shown on large screens during the exercise to relay information and prompt discussion among the players.

Clade X Exercise Presentation Slides


Fact sheets

National High-Level Patient Capacity
Caracas, Venezuela
Continuity of Government
Deployed Military Personnel
Federal Pandemic Response Plans
Fever Screening History and Capacity/Realities
Trade and Travel—Germany
US Healthcare Surge and Crisis Standards of Care
Nipah Virus
Parainfluenza Vaccine Status
Parainfluenza Immunity
Priority Population Statistics
Sequencing of Parainfluenza
US Borders and Infectious Disease
US Critical Infrastructure
US Emergency Authorities
US Public Health Programs and Assets to Respond to a Pandemic
Trade and Travel—Venezuela
Ventilator Stockpiling and Availability in the US and Internationally
WHO Capacities and Assets


Background materials

A Brighter Dawn
Clade X Model
Clade X Pathogen Engineering Assumptions


Segment 1

Segment 2

Segment 3

Segment 4


View pictures from Clade X here.


Clade X Media Coverage

Washington Post
What would happen if there were a worldwide pandemic?

Why another flu pandemic is likely just a matter of when

Washington Post
This mock pandemic killed 150 million people. Next time it might not be a drill.

The New Yorker
The terrifying lessons of a pandemic simulation

MIT Technology Review
It’s fiction, but America just got wiped out by a man-made terror germ

Mock pandemic ends in millions dead

Science Friday (NPR)
Center for Health Security hosts Clade X pandemic exercise

Business Insider
A leading medical institution created a simulation that shows how a new disease could kill 900 million people — and it reveals how unprepared we are

A pandemic killing tens of millions of people is a real possibility — and we are not prepared for it
“Designer bugs”: how the next pandemic might come from a lab

New England Journal of Medicine
Politics and Pandemics ("Perspective" column by Ron Klain)

Washington Post (op-ed)
Our lack of pandemic preparedness could prove deadly

Agenda (World Economic Forum blog)
6 ways countries can prepare for the next infectious disease pandemic

Fox News
Emergency preparedness drill exposes gaps in response after mock virus 'kills' 900M

Securing the US from its most dangerous invader: infectious disease

Toronto Sun
Next pandemic could kill a billion people: researchers (Australia)
How a virus attack just ended the world (sort of)
Also in Queensland Times, The Morning Bulletin, and Perth Now

New York Post
The world is completely unprepared for the next pandemic

The Week (UK)
Global pandemic could wipe out 900 million people

War on the Rocks
Death in the air: Revisiting the 2001 Anthrax mailings and the Amerithrax investigation

The Evan Solomon Show, 580 CFRA (Canada)
A group of scientists say the world is not ready for the next pandemic... and the death toll could reach 1 billion

Contagion Live
Clade X Simulation Reveals United States is Not Prepared for Severe Pandemics

Daily Mail (UK)
A global pandemic of a flu-like virus could kill 900 million people if it started to spread tomorrow, experts warn
G20 experts stage a fake superbug pandemic to test how the world would react to a deadly outbreak of an antibiotic-resistant disease

PA Times (ASPA)
Clade X is more than an exercise, it is a call to action

Global Health Now
Clade X: A mock, yet entirely plausible, pandemic

Business Insider
The FDA just approved a drug to treat smallpox in case of a bioterrorism attack — here’s why that scenario is so scary

Homeland Preparedness News
Mock Clade X pandemic decimates human population; denotes global pre-planning needs

Homeland Preparedness News
Clade X: Simulated pandemic to put political leaders, public on notice

Homeland Security Newswire
Clade X pandemic exercise: Preventing the worst outcomes in future pandemics

Washington Post
The many ways our world could end

  • Aspen Institute (11/29/18)
  • Johns Hopkins Bloomberg School of Public Health (10/31/18)
  • Center for Strategic and International Studies (10/2/18)
  • US Centers for Disease Control and Prevention (9/17/18)
  • International Conference on Emerging Infectious Diseases (8/28/18)
  • Biological Weapons Convention (8/15/18)
  • US congressional staff (7/17/18)


Exercise inquiries

Subject matter questions about Clade X should be directed via email to Eric Toner, MD, exercise team lead and senior scholar at the Center.

Media inquiries

Members of the media who have questions about Clade X should email