People ride bicycles on the National Mall in Washington, D.C., the United States, Aug. 30, 2020. (Photo by Ting Shen/Xinhua)

"Those are preventable deaths of our loved ones that we can just not let happen under our watch," an emergency physician told CNN.

WASHINGTON, Sept. 1 (Xinhua) -- About 2 million Americans could die in an attempt to try to achieve so-called herd immunity in the country, a U.S. medical expert said on Monday.

"If we're waiting until 60 percent to 80 percent of people have it, we're talking about 200 million-plus Americans getting this," Leana Wen, emergency physician, told CNN, adding that "at a fatality rate of 1 percent ... that's 2 million Americans who will die in this effort to try to get herd immunity."

"Those are preventable deaths of our loved ones that we can just not let happen under our watch," Wen added.

Likewise, if the United States allowed the coronavirus to spread unchecked in the effort to achieve herd immunity, the "death toll would be enormous," Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, warned in August.

"If everyone contracted it, even with the relatively high percentage of people without symptoms ... a lot of people are going to die," Fauci said during a live Instagram session.