The 10-time women's champion hasn't wrestled since beating Shayna Baszler on the March 1 edition of Raw. One week later, Flair signaled her desire to challenge Raw women's champion Asuka at WrestleMania 37.
WWE announced Monday night Asuka will defend the belt against Rhea Ripley.
The Wrestling Observer Newsletter's Dave Meltzer reported March 15 that WWE was experiencing a COVID-19 outbreak at its Performance Center, though it's doubtful Flair's announcement is connected to that report.
The promotion has been running main roster shows out of Tropicana Field in St. Petersburg, Florida, a good distance away from the Performance Center near Orlando. Meltzer added he didn't receive any indication the outbreak affected members of the Raw or SmackDown roster.
Assuming she makes a full recovery, Flair's positive test may not disrupt whatever WWE has planned for her at WrestleMania 37.
The company announced Jan. 11 that Drew McIntyre had been diagnosed with COVID-19. That didn't preclude him from successfully defending the WWE Championship against Goldberg at Royal Rumble 20 days later.