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Biden tests positive for COVID-19 again. What we know about COVID rebound cases

The President's repeat positive test highlights a phenomenon that can happen with or without antiviral treatment.

WASHINGTON — The President’s positive COVID-19 test so soon after recovering from the virus is raising a lot of questions about rebound cases, which appear just as likely to occur with or without his course of treatment.

RELATED: Biden tests positive for COVID-19 again in rare 'rebound' case


What do we know right now about COVID-19 rebound cases?



Over the course of the pandemic we’ve learned not only can you get COVID-19 more than once—these positive tests can happen quickly. Now we’re seeing that the same infection can even rebound and make you sick all over again–like in President Joe Biden’s case.

RELATED: Doctor: Biden tests positive for COVID for 2nd day in a row

“Even if you're kind of tired of this, the virus is not tired of us,” said Dr. Stuart Ray with Johns Hopkins. “This is a pattern we're seeing that people will report that they recently had COVID. And now they're sick again.”

A CDC health advisory defines COVID-19 rebounds as a recurrence of symptoms or a new positive test after having tested negative, happening two to eight days after initially recovering from the virus.

“The virus may be sort of evolving in that person, or might just simply be replicating in that person for a while, and then it gets the upper hand, at least for a while and causes a rebound,” explained Dr. Ray. 

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This happens in 2 to 8 percent of COVID cases, according to White House data—in a July 21 Press Briefing, Dr. Ashish Jha said all information he’s seen shows it’s “not that common.” 

In President Biden’s case, the rebound case happened after treatment with Paxlovid, an antiviral authorized to treat COVID-19 symptoms.

In its official guidance to healthcare providers, the FDA points to the drug’s clinical trial, in which the number of rebound cases is the same in people treated with Paxlovid as those who received a placebo: less than 2 percent.

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“We think that rebound may happen intrinsically by the virus, simply coming back up again. And that's seen with or without antiviral treatment,” said Dr. Ray.

The CDC continues to recommend Paxlovid for COVID-19 patients at high-risk for getting severely sick–and patient isolation for anyone with a positive COVID-19 test, even after taking Paxlovid or in a rebound case. The CDC says these rebound cases they’ve recorded are mild though, and at this time it’s not recommended someone get another round of antiviral treatment. 

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