Ahead of this year's Thanksgiving holiday, the Centers for Disease Control and Prevention warned Americans not to travel amid surging COVID-19 cases across the country.
"I can't see how we're not going to have the same thing [for Christmas]," he told Martha Radditz during Sunday's episode of "This Week" on ABC.
Fauci said coronavirus rates are rising and will not "suddenly turn around."
"Perhaps two or three weeks down the line, we may see a surge upon a surge. We don't want to frighten people, but that's just the reality," he said. "We said that these things would happen as we got into the cold weather and as we began traveling, and they've happened. And it's going to happen again."
BREAKING: “There almost certainly is going to be an uptick because of what’s happened with the travel,” Dr. Anthony Fauci tells @MarthaRaddatz, advising the millions of Americans who travelled for the holidays despite a surge in cases to get tested. https://t.co/2H5BGOYzMR pic.twitter.com/otD9N1TUB6— This Week (@ThisWeekABC) November 29, 2020
He also warned that "there almost certainly is going to be an uptick because of what's happened with the travel" over the past week. According to Transportation Security Administration data, 1 million passengers traveled through airports on Saturday, and Sunday is expected to be the busiest air travel day since the pandemic hit the U.S.
"We understand the importance of families getting together, and it's just something that we have to deal with that we likely will have an increase in cases," Fauci said.
He urged anyone who may have been exposed to the virus to be careful and also "pleaded" with Americans to follow the standard protocols for preventing the spread of COVID, like mask-wearing and social distancing.
"Help is on the way," he reminded viewers. "Vaccines are really right on the horizon."
The U.S. surpassed 13 million COVID-19 cases on Friday, an increase of more than a million cases in six days, according to data from Johns Hopkins University. More than 265,000 people have died.
As of Saturday, coronavirus hospitalizations are increasing in 46 states, Washington, D.C. and Puerto Rico and 13 states hit a record number of new cases, 26 states hit a record number of current hospitalizations and 12 states hit a record number of new deaths in the past week.
ABC News contributed to this report.