Potentially, one in every hundred people who contract the virus will die.
Coronavirus is ten times more deadly than influenza, one of the country's top health officials has warned.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told the House Oversight Committee on Wednesday that while the seasonal flu kills one in every thousand, COVID-19 could potentially kill one in every hundred.
"The seasonal flu that we deal with every year has a mortality (rate) of 0.1 percent," he explained.
While the stated death rate for coronavirus is 3 percent, he said that even when that was diluted with all the cases with mild or even no symptoms, "that probably brings the mortality rate down to somewhere around 1 percent - which means it is ten times more lethal than the seasonal flu."
"I can say we will see more cases, and things will get worse than they are right now," he said.
"How much worse we'll get will depend on our ability to do two things: to contain the influx in people who are infected coming from the outside and the ability to contain and mitigate within our own country," he added. "Bottom line: It's going to get worse."
He said that even in areas with little or no reported cases, behavior has to change.
"We have to essentially assume that we are going to get hit," he warned. "And that's why we talk about making mitigation and containment in a much more vigorous way."
"People ask: 'Why would you want to make any mitigation? We don't have any cases.' That's when you do it."
Dr Fauci said the next four weeks were critical in how bad the country was going to be affected.
"We cannot look at it and and say 'well, only a couple of cases here, that's good'," he warned. "Because a couple of cases today are going to be many, many cases tomorrow."
Just hours after his testimony, the World Health Organization officially classified novel coronavirus as a global pandemic.