as dr Anthony Fauci contracted Covid in June, he was taking Paxlovid, an antiviral drug for people with mild to moderate symptoms whose age or immune status puts them at high risk of serious illness. The treatment consists of three pills taken twice a day for five days.
Fauci ended treatment and tested negative for Covid. But about three days later, his test came back positive. His symptoms – runny nose, sore throat and fever – also reappeared.
A small minority of people taking Paxlovid see a similar rebound effect.
“Generally speaking, if you look at the studies, it doesn’t happen very often,” Fauci, who directs the National Institute of Allergy and Infectious Diseases, told MSNBC’s Morning Joe on Tuesday. However, he noted that there have been “anecdotal cases” suggesting rebounds are more common today than in clinical trials.
About 1-2% of people taking Paxlovid Clinical study by Pfizer tested positive for the corona virus after a negative test. Rebound rates are about 5% among the tens of thousands of people who have taken the drug in real-world settings, said Dr. Ashish Jha, coordinator of the White House Covid response, at a news conference last week.
“If you look at Twitter, it feels like everyone has recovered,” Jha said. “But it turns out that there is actually clinical data.”
A small study in June found that less than 1% of Covid patients experienced symptom recovery, on average, about nine days after taking Paxlovid. in one larger study of 13,600 Covid patients who were not peer-reviewed, 6% saw their symptoms worsen in the month following treatment.
dr Aditya Shah, an infectious disease specialist at the Mayo Clinic who led the small study, said it’s difficult for people to self-diagnose a rebound case. Ideally, people would have proof that they tested positive, then negative, then positive again, he said.
The actual number of rebound cases “could be as high as 5-10%, but I don’t think it’s as common as the general community makes it out to be,” Shah said.
The Centers for Disease Control and Prevention said in May that symptoms usually come back two to eight days after stopping Paxlovid, if they come back at all.
People who continue to test positive for Covid can still be contagious, so the CDC recommends that people resume isolation for at least five days if their illness returns.
The treatment cannot be long enough
Some disease experts suspect Paxlovid therapy is too short to clear the virus in certain people.
“One theory is that your natural immunity just can’t kick in fast enough because you need to treat within five days of symptoms, which is pretty early in the disease process,” said Peter Gulick, associate professor of medicine at Michigan State University.
When someone takes Paxlovid, “it probably lowers that viral load to a point where the body clinically doesn’t respond to it with any kind of inflammation,” Gulick said. That would explain why the symptoms initially disappear within about five days.
But some people may still have virus in their bodies, especially if they started out with a high viral load or the virus has spread to areas that medicines can’t easily reach. In this case, the symptoms could reappear.
“There might even be reservoirs,” Gulick said. “We don’t know Paxlovid’s ability to enter specific small areas of the body where the virus might reside.”
However, Shah is unsure whether an extension of the treatment course would benefit patients: “I would hesitate to say, ‘Yes, sure, take a 10-day course’ because there is no evidence to support this.”
Disease experts said it’s possible that elderly or immunocompromised people are more likely to experience a return of symptoms or test positive again after taking Paxlovid, but there’s no good data to support this theory yet.
In any case, rebound symptoms should be mild. A June CDC study found that less than 1% of people taking Paxlovid were admitted to the hospital or emergency room for Covid in the five to 15 days after stopping treatment.
“Paxlovid works really well and prevents major disease, rebound or no rebound,” Jha said last week. “That’s why the President took it.”
President Joe Biden ended his five-day Paxlovid course Monday. Experts said he should know if his symptoms have recovered in the next few days.
https://www.nbcnews.com/health/health-news/people-report-paxlovid-rebounds-covid-experts-insist-cases-are-rare-rcna40031 As more people report Paxlovid rebounds from Covid, experts insist the cases are rare