‘Paxlovid rebound’ more common than initially thought, doctors say

‘Paxlovid rebound’ more common than initially thought, doctors say

Six months ago, Dr. Joseph Boselli said he was prescribing the antiviral drug Paxlovid to nearly everyone who came to his office with COVID.

Now, the internal medicine doctor at Jefferson Health in Philadelphia said he’s reserving it primarily for people over 60, with serious illnesses. Health problems, or who are not up to date on their vaccinations.

“I got four calls today, but I only gave two Paxlovid because they were older,” said Boselli, an internal medicine doctor at Jefferson Health in Philadelphia.

After Paxlovid hit the market in December 2021, the bitter, metallic-tasting antiviral pills were so successful in reducing the risk of hospitalization from COVID that many doctors were willing to prescribe the drug to younger adults with no underlying health problems. despite federal guidelines suggesting it should only see high-risk patients.

PHOTO: Pfizer's Paxlovid

Pfizer’s Paxlovid

Joe Raedle/Getty Images, FILE

The medication prevents the virus from reproducing in the body and works best when taken within five days of the onset of symptoms.

Now, after more than 164 million cycles of Paxlovid have been shipped worldwide since April, doctors say a clearer picture of the drug is emerging, including its limitations with the younger population and the possibility of rebound, with or without the drug.

“The tincture of time has shown us that while it’s a great drug and it really works, it’s not for everyone,” Boselli said.

In a statement, Pfizer cited data from its 2021 clinical trials that found the risk of viral rebound after taking the drug is “rare and not uniquely associated with any specific treatment.”

“We did not see an association between viral rebound and severe disease or resistance,” the company wrote. “In addition, the vast majority of patients in (the trial) demonstrated sustained reductions in nasal viral RNA through day 14 after completing treatment.”

Here are three things you should know:

Paxlovid helps older people survive COVID, but younger, healthier people see little benefit

Overall, the drug works as promised, doctors say, dramatically reducing the chances that an elderly or high-risk person will end up hospitalized or dead.

Plus, it could help prevent “long COVID.”

A study released Monday by the Veterans Administration that analyzed the medical records of 56,000 people found that taking Paxlovid early lowered the chances of experiencing “long COVID” by 25%.

Still, the drug isn’t right for everyone, including people taking certain medications such as some cholesterol-lowering drugs and blood thinners.

PHOTO: Pfizer's Paxlovid

Pfizer’s Paxlovid

Joe Raedle/Getty Images, FILE

Additionally, a study published this summer found little or no benefit for younger adults, looking at some 100,000 patients in Israel. While the researchers found that the drug reduced hospitalization by about 75% when given shortly after infection to people older than 65, they saw no measurable benefit for people ages 40 to 64.

In June, Pfizer announced would stop enrolling “standard risk” patients in a trial to see if the general public might benefit.

In a statement at the time, Pfizer CEO Albert Bourla said: “With up to 40-50% of people worldwide estimated to be at high risk, we believe there remains a significant unmet need of treatment options to help combat this disease, and we will continue to prioritize efforts to advance the development of Paxlovid.”

‘Rebound’ Cases Are Real and Seriously Underestimated

Less understood about Paxlovid and COVID in general is a person’s “rebound” potential, a phenomenon in which a person recovers from an infection and tests negative, only to redevelop COVID symptoms or test positive within eight days after recovery.

The experience is frustrating because the recommendation is that the person return to isolation for another five days because it is believed that people who test positive during the rebound are still contagious.

The good news is that rebound cases are mild and mostly inconvenient, not life-threatening.

Initially, the chance of rebound after taking Paxlovid was thought to be very small, less than 2 percent in most cases, according to the Food and Drug Administration and Pfizer, the company that makes the drug.

But doctors say those estimates now seem too low compared to the number of rebound cases being reported, including high-profile White House examples.

President Joe Biden and his wife Jill; Biden’s top medical adviser, Dr. Anthony Fauci; and Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, experienced recovery.

Doctors interviewed by ABC News estimate that actual Paxlovid rebound ranges from 10 percent to 30 percent of cases, though no one knows for sure.

“I tell (patients) it’s very common,” said Dr. George Diaz of the Paxlovid Infectious Diseases Society of America.

But Diaz said he also tells patients that about a third of people who get COVID experience recovery even without treatment.

“There’s a good chance he’ll make a recovery, whether he takes treatment or not,” he said. And with Paxlovid, studies have found that it “significantly reduces the chance of hospitalization and death,” Diaz added.

US officials more concerned about COVID deaths than reports of a mild rebound

US health experts and regulators say they are more concerned that vulnerable patients will not receive the drug than that healthy people will recover.

PHOTO: Dr. Robert Califf awaits the start of a hearing before the Senate Committee on Health, Education, Labor and Pensions on November 17, 2015, in Washington, DC.

Dr. Robert Califf awaits the start of a hearing before the Senate Committee on Health, Education, Labor and Pensions on November 17, 2015, in Washington, DC.

Win Mcnamee/Getty Images, FILE

After Walensky ended his own case of Paxlovid, the CDC director noted that there are still some 400 deaths a day due to COVID and made it clear that there were no plans to withdraw the government’s recommendation of the drug.

Bob Califf, his FDA counterpart, agreed. He announced Monday that he tested positive for COVID over the weekend, and a spokesperson confirmed that he is being treated with Paxlovid.

“I am concerned that discussions of ‘Paxlovid rebound’ will distract us from the basis for (drug authorization): a substantial reduction in deaths and hospitalizations for high-risk patients,” he tweeted.

Dr. Judith O’Donnell, an infectious disease specialist at Penn Presbyterian Medical Center, said she agrees there are significant benefits for people over 50, as well as for younger patients with serious underlying health conditions, such as asthma, obesity, or kidney disease.

“The drug makes a real, measurable difference in the trajectory of the infection,” he said.

So “although there is a risk of rebound, that wouldn’t stop me from using it on the right patient,” he added later.

Youri Benadjaoud of ABC News Medical Unit contributed to this report.

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