Federal health regulators issued Tuesday a warning to COVID-19 patients who had received the antiviral Paxlovid on Tuesday. They warned that they may experience a rebound after a recovery period.
This warning comes nearly a month after thousands of patients began switching accounts on social media for COVID rebound after taking Paxlovid.
According to the Centers for Disease Control and Prevention, Paxlovid is still recommended for patients at high risk for severe complications. People with COVID-19 symptoms recurrences or new positive tests should isolate for at least five more days. The report also stated that people should wear masks for at least 10 days following rebound symptoms start.
Recent reports from researchers have shown Paxlovid rebounds among those who have been vaccinated or boosted, according to the warning CDC.
This warning comes after two provocative, but small, new studies by different research teams in New York and Boston that advise relapses like this may not be uncommon. Additionally, researchers observed that viral levels in some patients who had recovered from relapses were high enough to make them contagious.
One study also found that 2 people who relapsed by accident infected their family members. One case involved a 67-year man who had no symptoms 6 days following completion of Paxlovid and infected a 6-month-old family member. The transmission occurred within the time frame suggested by the CDC to isolate.
“This isn’t a rare disease; otherwise, why are these organizations forming?” The study looked at COVID infections in 10 patients aged 31 to 71 who had been properly vaccinated with at least one booster dose, according to Dr. Michael Charness (head of staff at VA Boston Healthcare System).
When there is a sign of infection, Paxlovid, an at-home medication for patients at high risk of COVID problems, is recommended. Three tablets are taken twice daily for five days.
In December, emergency authorization for Paxlovid drug manufacturer Pfizer was granted by federal regulators. The data showed that about 2% of the patients who participated in the trial of Paxlovid experienced a rebound. This is in contrast to approximately 1.5% of those who were given a placebo.
Although the Charness study does not refute the Pfizer data on rebounds directly, it suggests that patients who had completed Paxlovid experienced relapse symptoms that began between three to eight days and lasted for three to ten days.
Patients who were relapsing had their antigen test results show that they stayed positive for six days on average, and up to day 18 following their pre-Paxlovid positive initial test.
The Charness group compared a different group of COVID-19 patients that had not been treated with Paxlovid. It included nearly 1,000 people from the National Basketball Association. None of them had suffered a relapse from COVID. They have not published this data.
Dr. David Ho, head at the Aaron Diamond AIDS Research Center, Columbia University, and co-author of the Charness group and NBA studies, stated that “we cite the NBA data in order to say this clearly differs from what had been observed.”
A spokesperson for Pfizer said that the company continues monitoring data from current studies of Paxlovid as well as reports from physicians and rebound patients. All data “consistently with our observations” from Pfizer’s drug trial, he said.
In some patients, a COVID relapse, accompanied by a brief recurrence of symptoms, is a natural aspect of the SARS-CoV-2 (the disease that causes COVID-19) infection. Despite Paxlovid medication or immunization status, this warning is sent.
By May 14, data from the federal show that more than 6668,000 Paxlovid courses had been prescribed. Doctors claim that, despite recent rebounds in prescriptions of Paxlovid, the medicine is still effective and has kept at-risk patients out of the hospital.
Boston researchers conducted a second study on seven patients who had recovered from taking Paxlovid. They found that three of the seven patients had live virus levels for as long as nine days. One patient’s test specimen showed that the patient had been exposed to a live virus for eleven days after taking Paxlovid.
Dr. Mark Siedner of Massachusetts General Hospital, an infectious disease specialist and researcher, said “This raised the suspicion that they were contagious.”
It’s more than just that they rebound. Siedner stated that it’s not just that they rebound. It seems like they start at the beginning and their virus goes way up.” It’s an amazing phenomenon. Said Siedner. The team of Siedner found no evidence that the virus had developed resistance to Paxlovid. Siedner and other researchers believe that the rebound phenomenon raises urgent concerns about whether Paxlovid should be extended or if patients should be given another medication.
It stated that there was no evidence to suggest that Paxlovid or any other anti-SARS/CoV-2 therapies are needed in cases of COVID-19 rebound.
Siedner was intrigued by the reversals that featured such high levels of live virus and began to wonder if Paxlovid might have something to do with it.
He said, “It makes it wonderful, aren’t we using the drug properly, or for long enough? Or is there something about Paxlovid itself that doesn’t allow our immune system to kick in?”
The team that Siedner leads, which includes researchers from Women’s Hospital, Brigham, and the Broad Institute and Ragon Institute for MGH, MIT, and Harvard is introducing new research to try and answer some of these questions.
To determine if Paxlovid’s immune response is different in people who have recovered, they will examine the immune system of those who have received it.