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

Sen. Harris was once a proponent of the Green New Deal as both a co-sponsor of Sen. Bernie Sanders' bill and as a presidential candidate.

Since becoming Biden's running mate, Harris has moved away from her support, instead, embracing Biden's climate plan, which calls for the U.S. to rejoin the Paris Climate agreement, aims for the U.S. to get to net-zero carbon emissions by 2050 and invests $2 trillion in clean energy and infrastructure.

Fracking contributes to the economy in Pence's home state of Indiana and he's an advocate for the fossil fuel industry. He once called global warming a "myth," but has evolved slightly to say "there's no question" human activity has "some impact on climate change." He touts the economic sectors of oil, gas, fracking and coal as areas that boost job creation and the overall economy. He also hailed Trump for removing the U.S. from the Paris Climate Agreement, which he has called a "bad deal since the moment it was signed" by the Obama administration in 2015.

He also misleadingly told a group of farmers and ranchers in Iowa that he was not going to let Harris reduce the amount of red meat Americans should eat, referencing a comment she made during a 2019 CNN town hall as a way to curb the impact of climate change.

"Sen. Kamala Harris said she would change the dietary guidelines of this country to reduce the amount of red meat Americans can eat. Well, I've got some red meat for you. We're not gonna let Joe Biden and Kamala Harris cut America's meat."

Changing health guidelines does not necessarily mean Americans will be required to implement them, they are only recommendations.

During the 2019 town hall, Harris was asked if she "would support changing the dietary guidelines" in the U.S. to reduce red meat consumption and she answered, "yes." She said, "I love cheeseburgers from time to time," but that there needs to be more education surrounding "the effect of our eating habits on our environment."

-ABC News' Justin Gomez and Averi Harper