RNA - Congresswoman Rashida Tlaib made the remarks during a hearing of the House of Representatives with members of the president's coronavirus task force, confirming earlier reports by US media outlets including Axios and NBC News.
"Congress's attending physician told the Senate that he expects between 70 to 150 million people to eventually contract the coronavirus in the United States," Tlaib said.
Axios had reported that doctor Brian Monahan conveyed the projection to Senate senior staff on Tuesday, telling them they should prepare for the worst and offering advice on how to remain healthy.
The upper end of the projection is about 46 percent of the US population of 327 million people. By comparison German Chancellor Angela Merkel warned this week that up to 70 percent of her country's population could get the virus.
Asked by Tlaib whether he believed the projection was accurate, Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases (NIAID), told the hearing: "We really need to be careful with those kinds of predictions because that's based on a model."
He added that "all models are as good as the assumptions that you put into the model" and that with containment and mitigation the upper end of the projection could be avoided.
About 80 percent of coronavirus cases are mild, and the overall mortality rate is around one percent, according to the latest estimate provided by Fauci to Congress on Wednesday.
At the low end of the projection this would mean about 700,000 deaths. At the high end it would mean 1.5 million deaths.
Heart disease was the leading cause of death for Americans in 2018, with just over 650,000 deaths in 2018. The flu and pneumonia caused around 60,000 deaths.
As of Thursday, there had been more than 1,300 cases and 38 deaths, according to a tracker maintained by Johns Hopkins University.
Risk from coronavirus starts to increase for people who are over 60 and is heightened more for those over 80, as well as for people with conditions like diabetes, heart disease or lung disease, or whose immune systems are compromised.
Fauci noted that a 2014 model by the Centers for Disease Control and Prevention (CDC) projected the African Ebola outbreak could affect more than a million people. But this was eventually not the case and the final number was under 30,000.
'Failing' on access to tests
Fauci also responded to a query about people having difficulty getting access to tests, for which US authorities have come under severe criticism.
"The system is not really geared to what we need right now, what you are asking for. That is a failing," said Fauci. "Let's admit it."
"The idea of anybody getting it easily, the way people in other countries are doing it, we're not set up for that. Do I think we should be? Yes, but we're not."
Vice President Mike Pence, the White House's pointman for the crisis, claimed earlier this week that "a million tests are in the field" and four million would be going out soon.
But the CDC's director Robert Redfield said that the kits were not operational because there was a shortage of substances that activated them, called re-agents, and they also required more nasal swabs and trained staff.