Pete Buttigieg, the U.S. transportation secretary, tests positive for the coronavirus.

Transportation Secretary Pete Buttigieg said on Monday that he had tested positive for the coronavirus, the latest member of President Biden’s cabinet to be infected.

Mr. Buttigieg added that he was experiencing mild symptoms.

“I plan to work remotely while isolating according to C.D.C. guidelines, and look forward to when I can safely return to the office and the road,” he wrote on Twitter, referring to guidance from the Centers for Disease Control and Prevention.

Mr. Buttigieg was not considered a close contact of Mr. Biden, a White House spokesman said on Monday. To be a close contact, Mr. Buttigieg would have to have been less than six feet away from Mr. Biden for 15 minutes or more in a 24-hour period, according to the C.D.C.

The Department of Transportation said on Monday that Mr. Buttigieg, 40, has been vaccinated and boosted.

Mr. Buttigieg is one of at least 15 people who have tested positive for the coronavirus after attending the Mackinac Policy Conference in Michigan last week, according to the Detroit Regional Chamber, which organized the event. It is difficult to determine exactly how or when someone was exposed to and infected with the virus.

“The individuals testing positive report being asymptomatic or experiencing mild symptoms, and we wish them a speedy recovery,” the Detroit Regional Chamber said in a statement on Monday. In all, there were 1,347 attendees and support staff at the event, which ran from May 31 to June 3. They had to submit proof of vaccination or a negative P.C.R. test to attend the conference.

Gov. Gretchen Whitmer of Michigan, who also attended the event and spent time with Mr. Buttigieg, took a rapid test on Monday morning, “which came back negative,” according to Bobby Leddy, a spokesman. Mr. Leddy said that Ms. Whitmer, 50, “is fully up-to-date on her vaccinations, and is not currently experiencing any symptoms.”

Last week, Labor Secretary Martin J. Walsh and Interior Secretary Deb Haaland announced that they had also received positive test results.

Others in Mr. Biden’s inner circle who have tested positive in about the past month include Secretary of State Antony J. Blinken, Health and Human Services Secretary Xavier Becerra, and Susan Rice, the White House domestic policy adviser. Mr. Biden’s daughter, Ashley Biden, was also infected, in mid-May.