Fauci believes the worst of the COVID-19 pandemic could be ahead

Dr. Anthony Fauci expects more dire days ahead as the COVID-19 pandemic continues to rage on through the holidays.

The infectious diseases expert told CNN he agrees with President-elect Joe Biden's estimation that the worst of the pandemic could be ahead of us.

"The reason I'm concerned, and my colleagues in public health are concerned also, is that we very well might see a post-seasonal - in the sense of Christmas, New Year's - surge, and, as I have described it, as a surge upon a surge," Fauci said on CNN's "State of the Union" program.

"If you look at the slope, the incline of cases that we have experienced as we have gone into the late fall and soon-to-be-early winter, it is really quite troubling."

Last week, Biden said the "darkest days" of the pandemic are ahead of us.

On Sunday, Fauci expressed concern that the situation "might actually get worse" in the coming weeks.

There have been more than 63,000 confirmed deaths from coronavirus in the United States in December - the most of any month since the pandemic began.

Overall, the U.S. has reported the most coronavirus cases, with more than 18.9 million, and the most deaths, with more than 331,000, of any country since the start of the pandemic.

Fauci told CNN on Sunday that he estimates between 70% and 85% of people will need to be vaccinated for herd immunity to be reached.

More than 80 million cases of Covid-19 have been recorded worldwide, with more than 1.7 million deaths from the virus.