The showdown came as President Donald Trump and several in his orbit have tested positive for the novel coronavirus, raising questions on a transfer of power to the vice president were Trump at 74 -- or Democratic nominee Joe Biden at 77 -- to become too ill to serve.
The debate's format was divided into nine 10-minute sections with each candidate having two minutes to respond to the opening question in each segment and the remaining time allowed for follow ups. Moderator Susan Page, Washington Bureau chief of USA Today, did not release the topics in advance.
The sole vice presidential debate follows Trump and Biden's chaotic debate last week in Cleveland.
Here is how the news is developing today. All times Eastern.
Oct 07, 2020, 9:22 PM EDT
Trump plots return to campaign trail despite COVID-19 diagnosis
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
Oct 07, 2020, 9:17 PM EDT
First question on COVID-19 goes to Harris
Moderator Susan Page posed the first question to Harris, revealing the first of nine topics: The coronavirus pandemic.
Noting the president's recent diagnosis, Page asked Harris, "What would a Biden administration do in January and February that a Trump administration wouldn't do?"
Moderator and Washington bureau chief for USA Today Susan Page speaks before the vice presidential debate in Kingsbury Hall at the University of Utah, Oct. 7, 2020, in Salt Lake City.
Eric Baradat/AFP via Getty Images
True to her form as a prosecutor, Harris -- the first Black woman and first Indian American to take a vice presidential debate stage -- laid out her facts, arguing the administration knew about the threat of the virus in January but didn't act soon enough.
"They were informed that it's lethal in consequence, that it's airborne, that it will affect young people," Harris said. "They knew what was happening and they didn't tell you."
Harris then said the Trump administration still doesn't have a plan.
"Well, Joe Biden does and our plan is about what we need to do around a national strategy for contact tracing, for testing, for administration of the vaccine, and making sure that it will be free for all," she said.
There was no handshake between candidates -- customary at the top of such events -- due to COVID-19 precautions. The audience, limited to under 100 attendees, applauded Pence and Harris as they took the stage.
Former Democratic 2020 presidential candidate Pete Buttigieg, who played Pence at some mock debate rehearsals for Harris, was also spotted in the audience.
Former Democratic 2020 presidential candidate Pete Buttigieg, part of the Harris debate preparations team, waits for the start of the vice presidential campaign debate held in Salt Lake City, Oct. 7, 2020.
Brian Snyder/Reuters
Oct 07, 2020, 9:10 PM EDT
Debate is underway
Pence and Harris have taken the stage in Salt Lake City for the vice presidential debate. The candidates skipped the traditional handshake due to COVID-19 and are divided by plexiglass.
Oct 07, 2020, 9:05 PM EDT
Campaign chief of staffs weigh in on what to expect from their candidates’
Harris' chief of staff Karine Jean-Pierre told ABC News Chief Anchor George Stephanopoulos that Harris won't spend the night fact-checking Pence on stage.
Instead, the former prosecutor will "bring the case forward" on how Biden and Harris could lead to a different America.
"This debate is about Donald Trump's failure to contain COVID-19, and not just that but to also help working families," said Jean-Pierre, adding Harris has a "very diverse team" that has prepared her for the debate.
Jean-Pierre also criticized the example Trump has set since testing positive for the novel coronavirus last week.
"You have a president right now when he left the White House, he decided that he was going to make a campaign by removing his mask. His rhetoric has been incredibly dangerous," she said. "As Joe Biden said, it's a tragedy that he believes that he was blessed to have this virus, when people are suffering."
Marc Short, Pence's chief of staff, noted that Harris, like Pence, is "also a very skilled debater and has a record as a prosecutor, so I think it will be a very engaging conversation for the American people and hopefully one that shows a clear contrast in visions between the two campaigns."
Short said Pence will argue the case that the Trump administration protected more American lives in its COVID-19 response.
