During the first open discussion session, Page asked Harris if she would take a COVID-19 vaccine if it was approved by the Trump administration.

"If the public health professionals -- if Dr. Fauci, if the doctors tell us that we should take it, I'll be the first in line to take it, absolutely," Harris said. "But if Donald Trump tells us I should take it -- that we should take it, I'm not taking it."

Page tried to move on to the next topic -- the role of the vice president -- but Pence used his uninterrupted two minutes to respond to Harris' comment on a potential vaccine and to criticize how the Obama administration handled the Swine Flu or H1N1 pandemic of 2009.

"We have five companies in phase three clinical trials and we're right now producing tens of millions of doses," the vice president said.  "So, the fact that you continue to undermine public confidence in a vaccine, if a vaccine emerges during the trump administration, I think is unconscionable."

"And senator, I just ask you, stop playing politics with peoples' lives. The reality is, that we will have a vaccine, we believe, before the end of this year," he added.

In light of the president's recent diagnosis, Page directly asked Pence, "How can you expect Americans to follow the administration's safety guidelines to protect themselves from COVID when you at the White House have not been doing so?"

"Well, the American people have demonstrated over the last eight months that, when given the facts, they're willing to put the health of their families and their neighbors and people they don't know first," Pence said.

Pence also addressed the Sept. 26 Rose Garden event during which social distancing and masks weren't enforced and after which several White House officials tested positive.

"Many of the people who were at that event, Susan, actually were tested for coronavirus, and it was an outdoor event which all of our scientists regularly and routinely advise," Pence said. "The difference here is, President Trump and I trust the American people to make choices in the best interest of their health."

Pence defended the White House's response to the COVID-19 pandemic, saying that Trump "has put the health of America first." Pence pointed to the administration's early ban on travel to China, testing efforts and the efforts to research and administer a vaccine.

Pence also went after the plan the Biden campaign released to combat coronavirus, saying "it reads an awful lot like what President Trump and I, and our task force, have been doing every step of the way."

He said that the plan "looks a little bit like plagiarism," because of its similarity to the White House Coronavirus Task Force plan.

Harris hit back at Pence, citing the revelations that Trump downplayed the coronavirus to prevent panic.

"I want to ask the American people, how calm were you when you were panicked about where you were going to get your next roll of toilet paper, how calm were you when your kids were were sent home from school? How calm were you when your children couldn't see your parents because they were afraid they could kill them?" she said.

Trump's re-election campaign is looking to have the president return the campaign trail early next week, despite his COVID-19 diagnosis last Thursday and hospital stay over the weekend.

The campaign was forced to cancel five previously announced rallies due to the president's testing positive. Multiple sources tell ABC News the Trump team has begun working to nail down details for the president's return to the campaign trail and has considered an event -- possibly in Pennsylvania -- as early as next Monday.

ABC News' Will Steakin, Katherine Faulders and John Santucci

PENCE'S CLAIM: "It was an outdoor event, which all of our scientists regularly and routinely advise."

FACT CHECK: Vice President Mike Pence defended the 200-person event the Trump administration held at the White House on Sept. 26 when President Donald Trump announced he would nominate Judge Amy Coney Barrett to the Supreme Court -- despite the fact that over a dozen guests who attended have since tested positive, including the president and first lady Melania Trump.

While the main ceremony was held outside in the Rose Garden, numerous guests, including Trump, attended an indoor reception in the Diplomatic Room in the White House afterward. At least five people who attended the indoor portion of the event have since tested positive, including former New Jersey Gov. Chris Christie, Sen. Thom Tillis, R-N.C., and Sen. Mike Lee, R-Utah.

Public health experts have repeatedly advised against indoor events, which has found renewed importance in light of recent Centers for Disease Control and Prevention guidance advising that the virus can spread beyond 6 feet indoors.

Even for outdoor events, public health experts encourage wearing masks and maintaining 6 feet of distance from others. The Rose Garden event did not follow either of these social distancing norms; chairs were not spaced out, few guests opted to wear masks and guests hugged and shook hands.

The coronavirus outbreak has infected "34 White House staffers and other contacts" in recent days, according to an internal government memo, an indication that the disease has spread among more people than previous known in the seat of American government, according to an ABC News report.

ABC News' Olivia Rubin and Leah Croll