The White House has decided not to trace the contacts of guests and staff members at the Rose Garden celebration 10 days ago for Judge Amy Coney Barrett, where at least eight people, including the president, may have become infected, according to a White House official familiar with the plans.

Instead, it has limited its efforts to notifying people who came in close contact with Mr. Trump in the two days before his Covid diagnosis Thursday evening. It has also cut the Centers for Disease Control and Prevention, which has the government’s most extensive knowledge and resources for contact tracing, out of the process.

Contact tracing is an essential piece of any outbreak investigation and is a key to stopping the virus from spreading further, especially after a potential “super spreader” event where many people may have been infected.