The 2020 US presidential election campaign has effectively been put in hold as a result of Donald Trump’s positive test for Covid-19.
With just 31 days until election day, and with early voting and postal ballots already being cast in large swathes of the country, Mr Trump’s enforced quarantine means he will not be able to leave the White House and return to the campaign trail until the middle of October.
At that point, it us unclear whether he would even want to risk becoming infected again, or passing on the disease to others, something his doctors would not want.
While there was no immediate word from Joe Biden’s campaign on Friday morning, the 77-year-old former vice president has always taken the threat of coronavirus much more seriously than Mr Trump.
Indeed, for much of the summer, his campaigning consisted of speeches live-streamed from his home in Wilmington, Delaware, leading to accusations from Mr Trump that he was scared to go out.
Such was the worry of senior Democrats that Mr Trump was busily campaigning across the country, invariably while not wearing a mask, that Mr Biden was persuaded to start some on the ground campaigning, which he undertook in some of the crucial swing states of the upper midwest, including Pennsylvania, Wisconsin and Michigan.
CNN medical correspondent Sanjay Gupta said it was even possible that Mr Biden had been exposed to the virus, after he debated with Mr Trump on Tuesday night in Ohio.
“[The administration needs to trace their contacts and start quarantining people who have been in close contact with somebody,” he said. “And that's going to be a very important policy, here, within the West Wing.”
The White House issued a new schedule for Mr Trump's activities on Friday that did not include his planned trip to Florida.
But the new schedule did suggest the president would be hosting a phone call at Friday lunchtime on Covid-19 support for vulnerable seniors.
Mr Biden is scheduled to campaign in Michigan on Friday.
Both states are swing states that could decide the US election, though whether Mr Biden would wish to travel while potentially having been put at risk himself, seems unlikely.
What also remains unclear is whether the development will have any impact on national polling, which currently has Mr Biden some clear way ahead of Mr Trump.
Mr Trump played down the virus in its early stages and has repeatedly predicted it would go away.
More than 200,000 people have died from Covid-19 in the United States alone, with the elderly and those with pre-existing conditions especially hard hit.
The president rarely wears a mask and has ridiculed others, including Democratic presidential nominee for doing so regularly. Health professionals say that face coverings are key to preventing the spread of the virus.
Additional reporting by Reuters.