At least 53 people have tested positive for the coronavirus after attending an A-list Washington dinner.

At least 53 people have tested positive for the coronavirus since attending the Gridiron Club and Foundation’s annual dinner last Saturday in Washington, the group’s president confirmed Friday.

The Gridiron Club dinner, an annual white roast between journalists and presidential administrations, took place at the Renaissance Hotel. But a night of good-natured banter turned into an outbreak of cases among Washington’s elite, including members of Congress, members of the president’s cabinet and journalists.

About 700 people attended the event, including the 628 guests seated in the ballroom, Gridiron organizers said. Participants had to show proof of vaccination, but not a negative test result, and face masks were not required during the program.

Among those who publicly announced they had been infected with the virus after attending the dinner were Commerce Secretary Gina Raimondo; Attorney General Merrick B. Garland; Valerie Biden Owens, the president’s sister; and Representative Adam B. Schiff of California.

President Biden did not attend the dinner.

The development that cases linked to the Gridiron dinner had exceeded 50 was first reported by The Washington Post.

On Wednesday, the cases appeared to be limited to just a few tables, but they have since appeared at additional tables. So far, no symptoms more serious than a sore throat or mild fever have been reported, said Tom DeFrank, editor of the National Journal and president of the Gridiron Club.

Members have been coming forward since Sunday to notify the club of positive cases, and the club has notified anyone sitting next to, across from or near an infected guest, DeFrank said. “That’s what we have done from the beginning and continue to do,” he added.

This year’s event was the return of the Gridiron Dinner after a two-year absence related to the pandemic. In 2020, the organization canceled the event just days before it was to take place. That year, Dr. Anthony S. Fauci, the nation’s top infectious disease expert, accepted an invitation but later declined less than two weeks before the event at the start of the pandemic, DeFrank said. . This year, Dr. Fauci was the first guest to accept the invitation, Mr. DeFrank added. “It gave us a bit of optimism,” Mr. DeFrank said, adding that if Dr. Fauci had refused, “it would have meant something to us.” Dr. Rochelle P. Walensky, director of the Centers for Disease Control and Prevention, was also at the dinner.

The number of new cases reported among those who attended the dinner has been declining since at least Wednesday, DeFrank said.

“We expect the downward trend to continue,” he said.