The New York Times, The Wall Street Journal and The Washington Post are among the major outlets that have declined to assign reporters to travel with Mr. Trump as he returns to the trail this week, saying they do not have assurance that basic precautions will be taken to protect reporters’ health…

At least three White House correspondents have tested positive for the coronavirus in the past two weeks, including a Times reporter who had traveled on Air Force One, Michael D. Shear.

Safety concerns may also complicate Mr. Trump’s tentative NBC town hall on Thursday, one of his last remaining chances to make his case before a large national audience. NBC executives have asked the White House for proof that their employees will not face undue risks at the event, according to two people familiar with discussions.