Donald Trump says one benefit of his wife catching Covid-19 is it proves they live together.

Speaking in Pennsylvania, where the President hopes to eat into Joe Biden's five point poll lead, he told a largely mask-free crowd: "And then our great First Lady tested positive.

"Thats, uh, well at least those rumours that we don't live together turned out to be false."

Mocking the reports, he said: "'She lives in a house some place in Virginia.'

"No, no. She lives with me. And she tested...I said that's the only good thing about her testing positive."

The President said his wife was "strong, and knocked it out."

The First Lady took longer to recover from the virus than the President - and was cancelled planned appearances with the President on the campaign trail due to a lingering cough.

At a small, in-person rally in Newtown, Pennsylvania, Trump mocked his opponent on Saturday for his criticism of the administration's record of fighting COVID-19, which has killed more people in the United States than in any other country.

"I watched Joe Biden speak yesterday. All he talks about is COVID, COVID. He's got nothing else to say. COVID, COVID," Trump told the crowd, some of whom did not wear masks.

He said the United States was "just weeks away" from mass distribution of a safe vaccine against COVID-19, which is pushing hospitals to capacity and killing up to 1,000 people in the United States each day. Trump gave no details to back up his remarks about an imminent vaccine.

Campaigning in the Midwest today, Trump repeated his false claim that greedy doctors were lying about the number of Covid-19 deaths in order to make more money.