The director of the U.S. Centers for Disease Control and Prevention, Rochelle Walensky, tweeted on Tuesday that she has recovered from COVID-19. Walensky again tested positive for COVID with mild symptoms on Oct. 31 after completing a course of Pfizer's Paxlovid, having contracted the infection on Oct. 22

Walensky is the third senior government executive, after U.S. President Joe Biden and National Institute of Allergy and Infectious Diseases Director Dr Anthony Fauci to experience recurrent viral infection following the first course of Paxlovid.

Some people who took the antiviral drug have suffered from a relapse or a rebound soon after the five-day treatment course, studies have shown. 

• CDC Director Experiences COVID Rebound