One of the agency’s top disease modelers, Matthew Biggerstaff, presented the group on the phone call with four possible scenarios — A, B, C, and D — based on characteristics of the virus, including estimates of how transmissible it is and the severity of the illness it can cause. The assumptions, reviewed by the New York Times, were shared with about 50 expert teams to model how the virus could tear through the population — and what might stop it.

Officials at the US Centers for Disease Control and Prevention and epidemic experts from universities around the world conferred last month about what might happen if the new coronavirus gained a foothold in the United States. How many people might die? How many would be infected and need hospitalization?


The CDC’s scenarios were depicted in terms of percentages of the population. Translated into absolute numbers by independent experts using simple models of how viruses spread, the worst-case figures would be staggering if no actions were taken to slow transmission.

Between 160 million and 214 million people in the US could be infected over the course of the epidemic, according to one projection. That could last months or even over a year, with infections concentrated in shorter periods, staggered across time in different communities, experts said. As many as 200,000 to 1.7 million people could die.

And, the calculations based on the CDC’s scenarios suggested, 2.4 million to 21 million people in the US could require hospitalization, potentially crushing the nation’s medical system, which has only about 925,000 staffed hospital beds. Fewer than a tenth of those are for people who are critically ill.

The assumptions fueling those scenarios are mitigated by the fact that cities, states, businesses, and individuals are beginning to take steps to slow transmission, even if some are acting less aggressively than others. The CDC-led effort is developing more sophisticated models showing how interventions might decrease the worst-case numbers, though their projections have not been made public.


“When people change their behavior,” said Lauren Gardner, an associate professor at the Johns Hopkins Whiting School of Engineering who models epidemics, “those model parameters are no longer applicable,” so short-term forecasts are likely to be more accurate. “There is a lot of room for improvement if we act appropriately.”

The Times obtained screenshots of the CDC presentation, which has not been released publicly, from someone not involved in the meetings. The Times then verified the data with several scientists who did participate. The scenarios were marked valid until Feb. 28 but remain “roughly the same,” according to Ira Longini, co-director of the Center for Statistics and Quantitative Infectious Diseases at the University of Florida. He has joined in meetings of the group.

The CDC declined interview requests about the modeling effort and referred a request for comment to the White House Coronavirus Task Force. Devin O’Malley, a spokesman for the task force, said that senior health officials had not presented the findings to the group, led by Vice President Mike Pence, and that nobody in Pence’s office “has seen or been briefed on these models.”

The assumptions in the CDC’s four scenarios, and the new numerical projections, fall in the range of others developed by independent experts.

“A fire on your stove you could put out with a fire extinguisher, but if your kitchen is ablaze, that fire extinguisher probably won’t work,” said Dr. Carter Mecher, a senior medical adviser for public health at the Department of Veterans Affairs and a former director of medical preparedness policy at the White House during the Obama and Bush administrations. “Communities that pull the fire extinguisher early are much more effective.”


The four scenarios have different parameters, which is why the projections range so widely. They variously assume that each person with the coronavirus would infect either two or three people; that the hospitalization rate would be either 3 percent or 12 percent; and that either 1 percent or a quarter of a percent of people experiencing symptoms would die. Those assumptions are based on what is known so far about how the virus has behaved in other contexts, including in China.