Scramble under way in Washington to trace spread of Covid among US leadership

A scramble is under way in Washington to determine how far coronavirus infection has spread in the top ranks of US leadership after Donald Trump tested positive, in a week that included a presidential debate, political rallies and White House meetings with Congress.

The Democratic challenger for the presidency, Joe Biden, tested negative on Friday after fears he could have been infected at Tuesday’s debate with Trump in Cleveland. Further tests will be required as it can take several days after initial exposure to the virus for symptoms, and a positive test result, to emerge.

Related: Trump's positive Covid test was a surprise that many saw coming

A large White House contingent travelled to and from Ohio at close quarters in Air Force One without masks. The administration began a contact-trace operation on Thursday and the scale of the search widened as it became clear that Trump had continued campaigning – flying to Minnesota on Thursday – after Hope Hicks, a close adviser, had tested positive. Some senior officials did not find out until Thursday night, when they were informed by journalists about Hicks. It is not known who infected Trump or Hicks.

Mark Meadows, the White House chief of staff, said on Friday: “I fully expect that as this virus continues to go on other people in the White House will certainly have a positive test result.”

Meadows said that some “core staff” had tested negative, including himself, his deputy for communications, Dan Scavino, and the president’s son-in-law and adviser, Jared Kushner. He did not name anyone that tested positive.

Meadows was briefing the press without wearing a mask. On Friday afternoon, the national security adviser, Robert O’Brien, ordered masks to be worn in common areas of the White House, but the order did not apply to individual offices.

It emerged on Friday that infection could have started to spread in senior administration and Republican ranks as early as Saturday. The president of Notre Dame University, John Jenkins, announced he had tested positive. Jenkins had attended an event in the White House Rose Garden on Saturday for the nomination of Amy Coney Barrett as a supreme court justice, at which very few masks were worn.

The Republican Senator Mike Lee, who was videoed touching and hugging other guests at the same event, said on Friday he had also tested positive. Lee said he began to feel sick on Thursday morning, when he attended a meeting of the Senate judiciary committee, maskless for at least some of the time. He spoke for about 10 minutes, shouting some of the time, close to other senators on the committee, according to HuffPost.

Another Republican senator who was in attendance at the Rose Garden ceremony, Thom Tillis, also announced Friday he had tested positive for the virus. Kellyanne Conway, a former counsellor to the president, also said she had tested positive.

Barrett herself tested negative, the White House said on Friday. The Washington Post reported that she had caught the disease over the summer but made a full recovery. Lee’s infection calls into question the 12 October start date for her confiirmation hearings.

The vice-president, Mike Pence, tested negative for the virus on Friday morning and remains in good health, his spokesman said. The state department confirmed that the secretary of state, Mike Pompeo, currently travelling in Europe, also tested negative, and the Pentagon confirmed the defence secretary, Mark Esper, had a negative test result.

Trump’s children along with other senior White House staffers accompanied Trump from Washington to the Cleveland debate and back. Trump’s entourage wore masks as they entered the debate venue on Wednesday evening but then most took them off in defiance of the recommendation of the debate organisers. None of them are reported to have worn masks on Air Force One.

The White House physician said on Friday that no other members of Trump’s family had tested positive.

The extent of the spread of Covid in the top tier of US politics will depend on when the president, Melania Trump and Hicks became infected.

According to the New York Times, Hicks began to feel unwell at a Trump rally in Minnesota on Wednesday. She flew back in a separate cabin on Air Force One and exited from the back of the plane.

Trump spoke to journalists on the White House south lawn on his way to his Minnesota on Wednesday, mingled with local politicians and held a fundraising meeting in the town of Shorewood, before flying to Duluth for a big campaign rally.

By Meadows account, Hicks’s positive test was confirmed on Thursday as the president’s helicopter, Marine One, was taking off on the way to a fundraising event in New Jersey.

Trump suggested in an interview on Thursday night, before his own positive test result, that Hicks could have been infected by police or soldiers at an official event.

“It’s very, very hard when you are with people from the military or from law enforcement. And they come over to you, and they want to hug you and they want to kiss you, because we really have done a good job for ’em. And you get close, and things happen,” Trump told Fox News.

Even after Hicks’s test result was confirmed, the president went ahead with the event at his golf club at Bedminster, where he took part in a fundraising reception and a roundtable meeting with supporters. The Trump Organization sent attendees at the two events an email on Friday, published by Vice News, advising them to get tested if they experienced symptoms.

Trump’s press secretary, Kayleigh McEnany, held a briefing for journalists at which she did not mention Hicks’s test result. She has said she was unaware of the news at the time. Two journalists in the White House pool have since tested positive.

As she had accompanied Trump on trips all week, Hicks should have been tested every day. However, if she was symptomatic from Covid infection on Wednesday, that raises questions about the testing. Normally symptoms do not appear for several days after infection, so it is possible Hicks was given false negative results from tests earlier in the week. The White House uses the Abbott ID Now test, which has been found to produce a significant percentage of false negatives.

The Republican National Committee confirmed on Friday that its chairwoman, Ronna McDaniel, had tested positive and had been staying at home since last Saturday. She last met Trump the previous day.