Updated

President Biden "played too loose" with COVID-19 guidelines established by the Centers for Disease Control after initially testing negative for the virus on Wednesday, a doctor says.

While Biden tested negative for COVID-19 on Wednesday, he tested positive for the coronavirus in a "rebound" case on Saturday morning, the White House doctor said in a letter.

White House Doctor Dr. Kevin O'Connor said in a letter that "rebound" coronavirus positivity cases happen with a small amount of people who are treated with Paxlovid. 

However, after testing negative for COVID-19 on Wednesday, Biden was seen at indoor White House events without a mask, which goes against CDC recommendations.

BIDEN TESTS POSITIVE FOR COVID IN 'REBOUND' CASE, DOCTOR SAYS

On Wednesday, Biden participated in a roundtable on the economy with members of his administration including Department of Treasury Janet Yellen, but was not wearing a mask during the discussion.

The CDC says that people who contract COVID-19 should "wear a well-fitting mask" until 10 days after being exposed to COVID-19. It's not clear where or when Biden contracted COVID, but he first tested positive for the virus on July 21, meaning he was indoors around others without a mask just 7 days after his first positive test.

"Wear a well-fitting mask for 10 full days any time you are around others inside your home or in public. Do not go to places where you are unable to wear a well-fitting mask," the guidelines state.

Dr. Marc Siegel, Fox News medical analyst and professor of medicine at New York University Langone Medical Center told Fox News Digital that the president isn't setting a good example for following the CDC's COVID-19 guidelines.

BIDEN TESTS NEGATIVE FOR COVID-19, WILL END ISOLATION, WHITE HOUSE PHYSICIAN SAYS

"Not a good look for a president who talks about mandates. He has played too loose with this," Siegel said. "The antigen test is predictive of low infectivity if negative but a high quality mask KN95 or better would have been a wise precaution."

He said that Biden "could have" spread the coronavirus during the indoor roundtable on Wednesday.

White House Press Secretary Karine Jean-Pierre said that Biden was not wearing a mask on Wednesday because the group was socially distanced.

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"They were socially distanced. They were far, far enough apart. So we made it safe for them to be together, to be on that stage," she said. "So he's going to continue to follow CDC guidance recommendation that individuals who have tested positive wear a mask, when around others for ten days after symptom onset."