Eight days out from a presidential election, the president of Fox News and key members of the network’s election team have been told to quarantine after they were exposed to someone who tested positive for the novel coronavirus.

Until they test negative for the virus three times in a row, the anchors will be broadcasting their shows from home, according to two people with knowledge of the situation, who spoke on the condition of anonymity to discuss private health matters.

The infected person was on a flight chartered to transport Fox News employees returning to New York from the Thursday night presidential debate in Nashville. The person tested negative before departing Nashville and positive after returning.

Those on the flight included Jay Wallace, the network’s president; Bret Baier, the chief political anchor; Martha MacCallum, anchor of Fox’s nightly news show “The Story”; as well as two other members of the network’s election team, Juan Williams and Dana Perino, who are co-hosts of “The Five.”

On Monday, Fox News sent a memo to employees confirming “a few positive COVID-19 cases” at the company. The company said it was tightening its existing protocols in all its buildings. “We know this election will be like no other and it will be exciting to witness it first hand, but only those employees who are critical to that night’s production will be permitted to work from” the main Fox News studios in Manhattan, according to the memo, which was reviewed by The Washington Post.

Everyone aboard the flight tested negative in rapid tests conducted by both Fox News and the Commission on Presidential Debates before the debate. Upon the return to New York, those on the flight were again tested immediately.

Fox News has been regularly testing its employees as some have returned to working on set. A Fox News spokesperson declined to comment, citing the privacy concerns of its employees. The news of the positive test result and subsequent orders to quarantine were first reported by the New York Times.

Some of the anchors have received the results of their first PCR tests, which were negative. It is unclear if there was more than one person who initially tested positive on the flight. But everyone aboard the flight is being tested repeatedly to determine if they need to continue quarantining.

The network engaged in contact tracing immediately after it learned of the positive test result Sunday.

Behind the scenes, Fox News has shown dedication to precautionary measures during the pandemic, including masks, social distancing and regular testing protocols.

But that attitude has not always been reflected on the air. In February and March, in the early days of the pandemic, key prime-time hosts such as Sean Hannity and Laura Ingraham frequently attributed concerns over the virus as a mere excuse for Democrats and media to attack President Trump.