The C.D.C. defines a close contact as an individual “who was within six feet of an infected person for at least 15 minutes starting from two days before illness onset” until the infected person went into quarantine. If Mr. Trump developed symptoms on Wednesday evening, as some officials believe, Mr. Pence’s attendance at the president’s afternoon news conference would not be covered. His interaction with Mr. Trump on Tuesday was not extensive, and the men were several feet from each other.
Mr. Pence and his advisers are often photographed without masks on the road, even after his press secretary, Katie Miller, tested positive in May.
The vice president drew criticism in April, when he did not wear a mask while touring the Mayo Clinic, the renowned medical center in Minnesota, in violation of its clearly stated policy that visitors should wear a protective face covering. At the time, he defended his behavior by saying that he did not need to wear a mask because he was tested regularly.
During the summer, however, Mr. Pence, the chairman of the White House coronavirus task force, began encouraging people in areas where the virus was surging to wear masks. “We encourage everyone to wear a mask in the affected areas,” Mr. Pence said in June while visiting the University of Texas Southwestern Medical Center in Dallas. “Where you can’t maintain social distancing, wearing a mask is just a good idea, especially young people.”
His top aides, however, have been behind a pressure campaign on scientists at the C.D.C. to put out data that would support the reopening of schools. One staff member said she was repeatedly asked by Marc Short, the vice president’s chief of staff, to get the C.D.C. to produce more reports and charts showing a decline in coronavirus cases among young people.
In addition to Mr. Pence, White House officials said that Jared Kushner, the president’s senior adviser and son-in-law, and Ivanka Trump, who both accompanied Mr. Trump to his debate with former Vice President Joseph R. Biden Jr. on Tuesday night in Cleveland, had also tested negative for the virus. Barron Trump, the president’s 14-year-old son, had tested negative, according to Stephanie Grisham, the first lady’s chief of staff.