Biden coronavirus adviser warns US facing ‘darkest’ days of entire pandemic

FILE - (L) Dr. Michael Osterholm, Regents Professor, McKnight Presidential Endowed Chair in Public Health, and director of the Center for Infectious Disease Research and Policy at the University of Minnesota and Minnesota Gov. Tim Walz (R). (Glen Stubbe/Star Tribune via Getty Images)

President-elect Joe Biden’s coronavirus task force member Dr. Michael Osterholm warned on Tuesday that the “virus is really dangerous” and the holiday season will be the worst "period of the entire pandemic."

“Right now, we have to have the public understand that this virus is really dangerous-- that if you share air with people in the public spaces or in your private home with people who you haven’t had bubbled experiences with, meaning that they have been out in public, then, you’re at risk,” Osterholm told FOX Business’ Maria Bartiromo on “Mornings with Maria."

Biden and Vice President-elect Kamala Harris on Monday announced their Transition COVID-19 Advisory Board to shape the administration's approach to combatting the coronavirus.

Osterholm, who will be one of 10 advisory board members on Biden's task force, doubled down on the president-elect projecting a “very dark winter” in terms of how the coronavirus will spread.

“Over the course of the next 12 to 14 weeks are likely to be the darkest period in this entire pandemic and that they [Americans] have to take this thing very seriously,” Osterholm stressed.

The U.S. became the first nation to top 10 million coronavirus cases Monday afternoon amid a recent surge in infections that's been described as the third wave of COVID-19, according to data from Johns Hopkins University.

Daily infections have topped 100,000 five times in the past seven days, including 131,420 on Saturday, according to Reuters.

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Osterholm stressed that pandemic "fatigue" and “pandemic anger,” along with people sharing indoor air and believing that the pandemic was just a politically motivated issue could lead to a major uptick in cases by the holiday season.

“It would not surprise me if by the time we got to the holidays we could be reporting over 200,000 cases a day,” Osterholm said.

When host Maria Bartiromo asked whether seeing 200,000 cases a day would “mean we have to shut down,” Osterholm responded: “If we have runaway cases, the economy will suffer miserably.”

Fox News' David Aaro and Brooke Singman contributed to this report.