US Secretary of State Antony Blinken tested positive Wednesday for Covid-19 and will shift to a virtual work schedule, the State Department said.

"The Secretary is fully vaccinated and boosted against the virus and is experiencing only mild symptoms," the department said in a statement.

Blinken has not seen President Joe Biden in person for several days and Biden is not considered a close contact, it said.

Spokesman Ned Price said that Blinken would no longer deliver a long-awaited speech on China policy scheduled for Thursday.

"He looks forward to returning to the Department and resuming his full duties and travels as soon as possible," the statement said.

Blinken was among guests who packed into a Washington hotel on Saturday evening for the annual White House Correspondents' Association dinner.

Trevor Noah, the comedian who introduced Biden, joked about the dinner being a "super-spreader" event.