Vice President Mike Pence’s chief of staff, Marc Short, has tested positive for coronavirus along with at least one other key adviser, raising the prospect of another outbreak within the White House less than two weeks before the election.

Pence has tested negative and will continue to campaign for President Donald Trump’s re-election, according to a statement from the vice president’s office announcing Short’s diagnosis. It said Pence was considered “essential personnel” under Centers for Disease Control and Prevention guidelines.

Short is Pence’s top aide, a constant presence at his side who frequently acts as a spokesman for the vice president. In the statement, Pence’s office acknowledged that he’s considered a close contact of Short under infection tracing procedures.

Pence traveled to Florida to deliver a campaign speech in Tallahassee on Saturday evening after learning of Short’s diagnosis, according to people familiar with the matter. Short, who tested positive earlier in the day, did not accompany him.

Pence is scheduled to campaign on Sunday in Kinston, North Carolina.

Earlier Saturday, Bloomberg News reported that one of Pence’s closest political advisers, Marty Obst, had tested positive on Wednesday, adding further to the cases in and around the White House.

Coronavirus has swept through the White House since September, infecting President Donald Trump, his wife and youngest son, and a number of top aides, including his campaign manager, his press secretary, and the chairwoman of the Republican National Committee. The outbreak has served as a punctuation mark on Trump’s handling of the pandemic, which polls show has been widely panned by voters.

The US is experiencing yet another surge of infections, with new cases exceeding 83,000 on Friday, a record. About 8.6 million Americans have contracted the virus so far and more than 225,000 have died.

The infections of Short and Obst — as well as Pence’s exposure — risk overshadowing the closing week of Trump’s re-election campaign. Trump has repeatedly said in recent days that the country is turning a corner on the pandemic, even with a spike in infections.

“The bottom line is we have to be vigilant, we have to be careful, we have to be everything, but we also have to get our lives back,” the president said on Saturday at a rally in Waukesha, Wisconsin. “We have to take our country back. It’s going away, it’s rounding the turn.”

Both Obst and Short have developed minor symptoms of Covid-19, the disease caused by the virus, according to people familiar with the matter.

Obst is not a government employee, but is frequently in contact with Pence and his staff and often visits the White House grounds. He was last around Pence about a week ago but wasn’t in close proximity to the vice president, two of the people said.

Obst was quiet on Twitter the day of his diagnosis, with just one retweet, but has since been active on the social media platform, posting criticism of Democratic presidential nominee Joe Biden.

Short and Obst declined to comment.

Another Trump ally, former New Jersey Governor Chris Christie, was hospitalized with Covid-19 after helping the president prepare for his first debate with Biden last month. Since recovering, Christie has issued a public mea culpa, declaring he was wrong not to wear a mask at the White House and urging Americans to follow the guidance of public health authorities.

Trump has seldom worn a mask before or after his illness and discourages it among his aides and people around him. The president wore a mask on Saturday when he voted in Florida.

Pence, after avoiding the West Wing during the outbreak that sickened the president, was in the building this week.

On Saturday, the vice president was photographed wearing a mask as he walked from Marine Two and boarded Air Force Two in Washington. He didn’t wear a mask during events in Lakeland or Tallahassee but was alone on stage, at a distance from other people. US Secret Service agents around him wore masks.

The CDC recommends that “essential personnel” wear a mask at all times in their workplaces for 14 days following exposure to someone infected with coronavirus and maintain social distancing, to the extent practicable.

Pence’s press secretary Katie Miller contracted Covid-19 in May.