Biden's case highlights coronavirus 'rebound,' experts say

RANDALLSTOWN, Md. -- A phenomenon known as coronavirus 'rebound' is in the spotlight after President Joe Biden tested positive for COVID-19 again Saturday morning following several days of testing negative.

Rebound positivity can happen to people who take Paxlovid, an anti-viral medication aimed at preventing death and hospitalization for patients with COVID-19.

"It's people who have tested positive after taking a course of Paxlovid and it can be people who develop symptoms later on, or sometimes if they tested negative, and if they've been tested again, they test positive," explained Dr. Kinjal Sheth.

The Chief of Critical Care Medicine at Northwest Hospital added that research indicates about 10% of people who take Paxlovid experience COVID rebound.

In late May, the Centers of Disease Control and Prevention issued a health advisory about the potential for reoccurrence of COVID-19.

Rebound positivity after taking Paxlovid can happen between 2 and 8 days after initially recovering from the virus, resulting in a return of symptoms or a new positive test after testing negative, according to the CDC.

The advisory notes that people who have been treated with Paxlovid and experience COVID-19 rebound have mild symptoms and there are no reports of severe disease.

The agency also stated there's no evidence that another treatment is needed with Paxlovid or other COVID-19 therapies in cases of rebound positivity.

The CDC recommends that you isolate for at least 5 full days, with day zero being the first day of symptoms or the date you test positive for asymptomatic cases.

The White House physician reports that President Biden is not experiencing any symptoms but continues to isolate.