B. Douglas Bernheim, the chair of Stanford University's Economics Department, told Fox News that he has "substantial concern" about the potential risk of a COVID-19 spread at recent celebrations for President-elect Joe Biden.

"I am watching the celebrations with substantial concern about the potential public health consequences," Bernheim said in an interview Sunday. "Going forward, it is important to learn as much as we can about COVID transmission at all types of social gatherings, including these." 

Bernheim recently led a study conducted by economists from Stanford’s Institute for Economic Policy Research, which examined the impact of 18 Trump rallies held between June 20 and Sept. 30 by comparing spread of the virus after each event to parts of the country that didn't host rallies.

"For the vast majority of these variants, our estimate of the average treatment effect across the eighteen events implies that they increased subsequent confirmed cases of COVID-19 by more than 250 per 100,000 residents," researchers wrote. "Extrapolating this figure to the entire sample, we conclude that these eighteen rallies ultimately resulted in more than 30,000 incremental confirmed cases of COVID-19. Applying county-specific post-event death rates, we conclude that the rallies likely led to more than 700 deaths (not necessarily among attendees)."

President Donald Trump walks off stage after speaking during a campaign rally at Wilkes-Barre Scranton International Airport, Monday, Nov. 2, 2020, in Avoca, Pa. (AP Photo/Evan Vucci)

President Donald Trump walks off stage after speaking during a campaign rally at Wilkes-Barre Scranton International Airport, Monday, Nov. 2, 2020, in Avoca, Pa. (AP Photo/Evan Vucci) (AP)

#FACTSFIRST: JAKE TAPPER, CNN'S CORONAVIRUS DOUBLE STANDARD ON TRUMP AND BIDEN RALLIES EXPOSED

When asked by Fox News about whether the celebrations would lead to a spike in coronavirus cases or deaths, Berheim only noted that many Biden supporters were seen wearing masks -- although he added that it is unclear "the extent to which this practice mitigates the effects" of the virus' spread.

"As we explained in the paper and in various interviews, these methods require us to be able to identify comparable jurisdictions with and without gatherings of a particular type, and to obtain a complete catalog of those gatherings," Bernheim said. "Because coverage of the celebrations shows widespread use of masks, it is worth emphasizing that we do not yet know the extent to which this practice mitigates the effects found in our study."

He added that it would be difficult to determine if the statistical methods used by Stanford's Trump rally study would be "applicable" to studying the Biden celebrations given their spontaneity.

"For the same reason, to the extent compliance with public health guidelines increased at Trump rallies held after the ones we studied (as the Trump campaign has claimed), we do not yet know whether these methods were effective," he said.

Bernheim did, however, argue that Biden should address his supporters about the health risks the celebrations pose.

"I would recommend to the President-elect that he strongly encourage adherence with public health guidelines," Bernheim said. "My own advice to his supporters is to celebrate at home."

BIDEN SILENT ON LACK OF SOCIAL DISTANCING, POSSIBLE 'SUPER SPREADER' CELEBRATIONS

White House Press Secretary Kayleigh McEnany called on the president-elect on Saturday to tell his supporters to end what she described as "massive Super Spreader events held in his name."

The crowds also caught the attention of comedian Tim Young, who blasted CNN for what he viewed as a double standard between Supreme Court Justice Amy Coney Barrett's confirmation hearing and the Biden celebrations. 

"CNN called Amy Coney Barrett's confirmation in the Rose Garden - where 100 people were masked and sitting 6 feet apart - a "Super-spreader event", Young tweeted. "That same CNN was cool with THOUSANDS of liberals slobbering all over themselves in the streets for Biden yesterday."

CNN's Jake Tapper appeared to be the one of the few on the network who acknowledged the risk being posed by the celebrations during its coverage on Saturday. 

“I hate to be a scold here, but we just had the highest day of infections in the United States," Tapper said during a CNN panel discussion after Biden's victory. "I believe yesterday was 125,000 Americans with new coronavirus infections. That was the third straight day of more than 100,000 infections. It’s good to see people wearing masks -- although for some of them they’re slipping off their face."

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Bernheim's comments come less than 24 hours after Biden pledged that getting the coronavirus under control would be the first priority of his administration. 

"We cannot repair the economy, restore vitality or relish life's most precious moments - our grandchildren, our children, our birthdays, weddings, graduation, all the moments that matter most to us - until we get it under control," Biden said.

Biden said that he will name a group of leading scientists and health experts as "transition advisers" on Monday to create a COVID "action blueprint" that will begin after he is sworn in Jan. 20. He noted that the his administration's plan will be built on "bedrock science" and constructed out of "compassion, empathy and concern." 

"I will spare no effort -- none -- or any commitment to turn around this pandemic," he added.

The United States has surpassed 9.9 million confirmed coronavirus cases and more than 237,000 related deaths, according to the latest update by Johns Hopkins University.