First lady Jill Biden has tested negative for COVID-19 and returns to Washington, D.C., on Tuesday.

Biden's communications director, Elizabeth Alexander, announced the results in a Monday evening statement.

The first lady had been isolating at her family's house in Rehoboth Beach, Delaware.

She first tested positive for the virus on Aug. 15 when she and the president were vacationing in Kiawah Island, South Carolina.

FIRST LADY JILL BIDEN TESTS POSITIVE FOR COVID-19 ONCE AGAIN IN REBOUND CASE

First lady Jill Biden visits the Congress Library, July 12, 2022 on Capitol Hill in Washington. (AP Photo/Mariam Zuhaib, File)

She tested positive a second time on Aug. 24 and, at that time, her spokesperson said she was not experiencing any symptoms.

Biden, who is 71, has been fully vaccinated and boosted twice with the Pfizer COVID-19 vaccine.

She was prescribed the antiviral drug Paxlovid.

First lady Jill Biden (R) and Mexican first lady Beatriz Gutierrez Muller tour the Library of Congress on July 12, 2022, in Washington, D.C. (Photo by Roberto Schmidt/AFP via Getty Images)

FIRST LADY JILL BIDEN TESTS NEGATIVE FOR COVID-19, IS DELAWARE-BOUND

Paxlovid is authorized for emergency use in people ages 12 and older who are at high risk for severe illness from the virus.

A minority of those who are prescribed Paxlovid have experienced a rebound case of COVID-19.

President Biden and first lady Jill Biden exit Marine One at Charleston Executive Airport in South Carolina on Wednesday, Aug. 10. (AP Photo/Manuel Balce Ceneta)

President Biden has also had a rebound case of the virus and was identified as a close contact of his wife.

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The White House said that the 79-year-old president was undergoing more frequent testing for the virus as a precaution.

The Associated Press contributed to this report.

First lady Jill Biden recovers from COVID again, returning to Washington

Biden first tested positive for COVID on Aug. 15 while vacationing in South Carolina