CDC Director Dr. Rochelle Walensky tested positive for COVID-19 again on Sunday, 10 days after initially contracting the virus. 

Walensky, who is up to date on her vaccines, started a course of Pfizer's antiviral drug Paxlovid when she first started developing symptoms on Oct. 21. 

Her symptoms improved and she tested negative, but she tested positive again in an apparent rebound case on Sunday. 

Dr. Rochelle Walensky

CDC Director Dr. Rochelle Walensky speaks during the COVID Federal Response Hearing on Capitol Hill on June 16, 2022 in Washington, DC.  (Joe Raedle/Getty Images)

Walensky is the third high-profile government official to experience a rebound COVID-19 case after taking Paxlovid, which was approved in December for patients at risk of severe infection. 

COVID-19 SYMPTOMS REBOUND AFTER PAXLOVID MAY BE DUE TO IMMUNE SYSTEM RESPONSE

President Joe Biden tested positive for COVID-19 in a rebound case in July after testing negative for four days. 

President Biden speaks

President Biden speaks at a press conference in Los Angeles.  (AP Photo/Damian Dovarganes)

Dr. Anthony Fauci debates Rand Paul

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testifies before Congress.  (Getty Images)

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Dr. Anthony Fauci, who is stepping down at the end of this year, also suffered a rebound case in June. 

Walensky is now isolating at home and working virtually, the CDC said.