US Democratic vice presidential nominee Kamala Harris has cancelled her travel plans after one of her staff members tested positive for Covid-19, the campaign said in a statement.
The campaign said that Ms Harris was last tested yesterday and was negative.
Her communications director, Liz Allen, had tested positive.
Ms Harris is expected to resume in-person campaigning on Monday.
A non-staff flight crew member also tested positive, campaign manager Jen O'Malley Dillon said in a statement.
Ms Harris did not need to quarantine, Ms O'Malley Dillon added, but "out of an abundance of caution" would cancel travel and campaign virtually before hitting the road again on 19 October.
Both individuals flew with the Democratic senator on 8 October.
All three were wearing masks, Ms O'Malley Dillon said.
Ms Harris has been tested twice since then, both producing negative results, the Democratic campaign said, and she had not been in contact with either individual for 48 hours before they tested positive.
The announcement is the latest interruption in a US presidential campaign that has been upended by the coronavirus pandemic, and comes two weeks to the day after President Donald Trump tested positive for the disease.