Jha: Here’s what you need to know about COVID ‘rebound’ as Biden goes back into quarantine

"I care less about rebound than I care about preventing serious illness. And Pax did that."

White House COVID-19 Response Coordinator Ashish Jha speaking at a press conference on July 25. Anna Moneymaker / Getty Images

Even with President Joe Biden testing positive for COVID-19 again on Saturday after he was cleared to exit isolation — in what is known as a “rebound” case — White House Coronavirus Response Coordinator Ashish Jha urges people not to distrust the Pfizer product Paxlovid that may have caused the rebound. 


Rebound cases have been repeatedly observed among people taking Paxlovid, an antiviral treatment from Pfizer that has been proven to reduce risk of hospitalization or death by nearly 90% in high-risk adults. Biden was administered Paxlovid, despite being vaccinated and boosted, for extra precaution when he first came down with COVID-19. 


Jha, currently on leave from his position as dean of the Brown University School of Public Health, took to Twitter Sunday evening to dispel worries, pointing out that even though some people who take Paxlovid are experiencing rebound cases, it’s still doing its job very well.

It’s important to be aware that rebound COVID-19 can happen, for contagion purposes, but generally, it’s not causing serious illness, he said.

Numbers are hard to know for sure, because most people, whether or not they take Paxlovid, don’t test again immediately after recovery, as Biden did. 

He said his guess is that about 5% of people who take Paxlovid rebound, which is a small minority. And people who don’t take Paxlovid can also rebound. 

“In the clinical trial, the placebo group had almost as much rebound as Paxlovid group,” Jha said. 

Jeremy Faust, a Brigham and Women’s doctor who writes the Inside Medicine newsletter, posted Saturday that his estimated number of people who rebound is about 15-35% of people who take the drug.

Though he agreed with Jha that Paxlovid is still good to take for preventing serious illness, rebound as a result of Paxlovid is problematic because of contagion, he wrote.


“People who have Paxlovid rebound may be falsely reassured that they’re no longer contagious,” he said. “If they leave isolation and subsequently become contagious again and infect others, they may have inadvertently spread the virus to those far less able to stave off the infection.”

It’s a possibility patients taking Paxlovid should be aware of, according to the CDC.

“If you get better and then you get worse again or if you decide to test and you have a test that’s positive, especially after a negative test result, the recommendation is to re-isolate for at least five more days and continue masking for at least 10 more days,” said Dr. Lauri Hicks, chief medical officer of CDC’s COVID-19 response, in USA Today.

But Jha, on Twitter, maintained that high risk people should still get Paxlovid despite the rebound possibility — “because I care less about rebound than I care about preventing serious illness. And Pax did that.”


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