The early morning news on Friday, Oct. 2, that President Donald Trump and first lady Melania Trump had tested positive for COVID-19 has cast another shadow of uncertainty on an already unprecedented election season.

Watch the conversation in the video player above.

The president and his wife are both displaying symptoms, though White House chief of staff Mark Meadows said they are mild. In a memo Friday afternoon, White House physician Sean Conley said Trump received a single 8-gram dose of Regeneron’s polyclonal antibody cocktail as treatment, adding that the president “remains fatigued but in good spirits.”

The White House released a statement on Friday– less than 24 hours after his positive test was announced– that the president was being moved to Walter Reed hospital. White House press secretary Kayleigh McEnany said that Trump “remains in good spirits” but will be moved to Walter Reed and working from there for the coming days “out of an abundance of caution, and at the recommendation of his physician and medical experts.”

The news of Trump’s diagnosis sparked a flurry of questions over the future of Trump’s campaign, the dozens of people he’s had contact with in recent days, as well as how the illness will affect his presidential duties.

PBS NewsHour’s William Brangham and Yamiche Alcindor answered questions from viewers about Trump’s COVID-19 diagnosis and what this means for the 2020 election.

How did the news of Trump’s diagnosis unfold?

Bloomberg News first reported on Thursday night that Trump’s senior adviser Hope Hicks had tested positive for COVID-19 on Wednesday. Shortly after, it was announced that the president and first lady had been tested and were awaiting results. Trump revealed in a tweet just before 1 a.m. that they both had tested positive.

“Tonight, @FLOTUS and I tested positive for COVID-19,” Trump tweeted. “We will begin our quarantine and recovery process immediately. We will get through this TOGETHER!”

In a memo shortly after Trump’s tweet, Dr. Conley wrote, “The President and First Lady are both well at this time, and they plan to remain at home within the White House during their convalescence.”

Trump’s Friday schedule, which was set to include a trip to a campaign rally in Florida, was cleared except for one phone call to discuss “COVID-19 support to vulnerable seniors.”

How could COVID-19 potentially affect Trump?

Trump is 74 years old, which puts him at higher risk of experiencing more severe COVID-19 symptoms. People between the ages of 65 and 74 are nearly five times more likely to be hospitalized for COVID-19 related complications than those between ages 18 and 29, according to June data from the Centers for Disease Control and Prevention. People 75 to 84 years old are about 7 times more likely to be hospitalized than the 18 to 29 age group.

“There’s no evidence that [Trump] is seeing or experiencing any conflicts or any particular serious symptoms as of right now,” Alcindor said to Brangham. “But I want to reiterate that we’re talking about a senior citizen, and someone who falls in the group of people that Dr. [Anthony] Fauci and so many other health officials have said have to be extra vigilant when it comes to this virus.”

Gary Simon, a medical doctor and director of the Division of Infectious Diseases at George Washington University, told the PBS NewsHour that it’s unclear at this point how the virus will affect Trump’s heath.

“It’s very hard to predict simply based on the epidemiology, how he’s going to do. Certainly he’s going to do worse than somebody with the same symptoms who’s 25 years old,” Simon said. “But the markers that predict disease are mostly laboratory markers, and we don’t know any of those.”

Throughout his first term the White House has been vague regarding the details of Trump’s health. Earlier this summer, Conley declared the president to be in good health and had repeatedly tested negative for COVID-19.

Who else may have been infected?

Simon said the president likely contracted the virus within the last 5 to 10 days. Since Thursday, Sept. 24, Trump has made public appearances or held meetings on at least 17 different occasions, including campaign rallies in Florida, Virginia, Pennsylvania and Minnesota.

Dozens of people have been in contact with the president in recent days, including lawmakers and White House aides. These individuals, in addition to the large rally crowds, could potentially have been exposed to the virus.

Trump and former Vice President Joe Biden stood in an enclosed auditorium together–but with space between them– neither wearing masks, for 90 minutes during Tuesday’s first presidential debate. Biden and his wife Jill both tested negative for COVID-19 on Friday, but test results in the first few days after exposure are not very reliable, as the incubation period can take as long as 10 to 14 days after exposure. Anyone who recently had contact with the president should take follow up tests during this period, Simon said.

Trump’s diagnosis immediately became fodder for criticism, as he has repeatedly downplayed the dangers of the coronavirus and his administration has provided inconsistent guidance on ways to mitigate its spread.

“[Trump] has been talking about the virus in a way saying that it’s going to be in the rearview mirror,” Alcindor said. “Just this week, he was making fun of Joe Biden for wearing a mask. … Now we’re seeing an outbreak, literally, in the headquarters of the United States.”

Will the presidential and vice presidential debates still happen?

The next debate will take place in Salt Lake City on Wednesday, Oct. 7, between incumbent Vice President Mike Pence and Biden’s running mate, Sen. Kamala Harris, D-Calif.

Pence and Harris both tested negative for the virus on Friday, but Pence was in the Oval Office with the president as recently as Tuesday, Pence told a Pennsylvania crowd that day. A memo released by Pence’s physician on Friday said Pence is not “considered a close contact with any individuals who have tested positive for COVID, including President Donald J. Trump.” The memo added that Pence “is free to go about his normal activities.”

The Commission on Presidential Debates confirmed on Friday that the vice presidential debate will still occur. The remaining presidential debates between Trump and Biden on Oct. 15 and Oct. 22 are still up in the air.

“I think it really questions whether or not the president is going to be able to debate while having the coronavirus. Also, is he going to be able to debate in person? Are we going to turn to Zoom debates?” Alcindor asked. “How is he going to travel to a debate and to multiple debates when he’s supposed to be quarantining for some 14 days, at least, if he’s not sick and experiencing my symptoms longer than that?”

What does this all mean for Trump’s reelection campaigning?

Guidance from the CDC and other infectious disease experts indicates that people who test positive for the virus and experience symptoms will be contagious for about 10 days after the symptoms resolve. It’s unclear at this point how long Trump may experience symptoms and whether he will be able to hold any more in-person campaign events before Election Day.

If Trump chooses, as he has done in the past, to defy public health guidance and hold in-person events while he is experiencing symptoms, there’s nothing that can reasonably stop him, Alcindor said.

“If the president says he wants to go somewhere, who would tell him that he can’t do that? He is the president of the United States. He’s the commander in chief,” Alcindor said. “He’s made being on the campaign trail, not social distancing, not wearing a mask, a central part of his thesis that the coronavirus is going away. Of course, again, there is no evidence of that.”

In a statement Friday afternoon, the Trump campaign said, “All previously announced campaign events involving the President’s participation are in the process of being moved to virtual events or are being temporarily postponed. In addition, previously announced events involving members of the First Family are also being temporarily postponed. All other campaign events will be considered on a case-by-case basis and we will make any relevant announcements in the days ahead.”

Will the diagnosis affect Trump’s presidential responsibilities?

Trump’s diagnosis has called into question how the illness will affect his ability to execute the duties of his position. Alcindor quoted one White House source who said it is “business as usual.” Officials have told her the president plans to continue his work from the White House.

Dr. Conley stated in his memo that he expects the president to be able to carry out his duties without disruption.

Simon of George Washington University said too little information is known at this point to predict how the virus will affect Trump. Should Trump face serious complications, he can invoke the 25th Amendment and declare to Congress, in writing, that he is too incapacitated to serve and will voluntarily, if even temporarily, relieve himself of those duties. This would invoke the line of succession and Pence would step up into the presidency until Trump recovers and is again able to fulfill his responsibilities, which the amendment gives the president the authority to decide.

The 25th Amendment could also be invoked on Trump’s behalf if he is deemed unable to fulfill his duties and cannot, or will not, step aside. It would take the vice president and a majority of Cabinet secretaries to declare the president “unable to to discharge the powers and duties of his office,” according to the Constitution.

White House correspondent Yamiche Alcindor, correspondent William Brangham and White House producer Meredith Lee contributed reporting.