Centers for Disease Control and Prevention (CDC) director Rochelle Walsensky issued a warning to people taking Pfizer’s Paxlovid that the drug could lead to a rebound in COVID-19 symptoms. Yet, the agency is pretending the benefits of the drug outweigh the risks.
“If you take Paxlovid, you might get symptoms again,” Walensky told CBS News on Tuesday. “We haven’t yet seen anybody who has returned with symptoms needing to go to the hospital. So, generally, a milder course.”
Paxlovid is an antiviral medication for COVID-19 — taken over the course of five days —developed by Pfizer.
After a patient recovers from COVID-19, the rebound appeared to occur between two and eight days later, according to the CDC. In addition, people who have a “COVID-19 rebound” after treatment with Paxlovid can be contagious even if they don’t have any symptoms, researchers warn.
The CDC, citing case reports and concerns that relapsed patients could spread the virus, advised users to isolate themselves for a second five days if symptoms rebound.
“I am shying away from giving it to people who are very low-risk, and are not terribly ill, particularly people who are vaccinated and boosted,” Dr. Bruce Farber, chief of public health and epidemiology for Northwell Health told Reuters.
Pfizer, in an email, said it is monitoring the issue but believes the return of detectable SARS-CoV-2 is uncommon and not “uniquely associated” with its drug. “We have not seen any resistance emerge to date in patients treated with Paxlovid,” a Pfizer spokesperson told Reuters.
Pfizer told CBS it is observing a rebound rate of approximately 2%.
Of course, this is the same company that is ignoring hundreds of thousands of adverse events, including deaths, reported in those who’ve received its Pfizer-BioNTech COVID-19 vaccine, so they’re not likely to admit their drug is a total flop.
“People who experience rebound are at risk of transmitting to other people, even though they’re outside what people accept as the usual window for being able to transmit,” Dr. Michael Charness of the Veterans Administration Medical Center in Boston told CNN on Tuesday.
Charness’ team of researchers said they observed people infect others in two instances after finishing treatment with Paxlovid. One case involved a 67-year-old man who infected a 6-month-old 12 days after finishing the drug and another involved a 63-year-old who infected two family members 3 days after a course of Paxlovid.
More quarantine time “is not a crowd-pleaser,” Dr. Sandra Kemmerly, an infectious disease specialist at Ochsner Health told Reuters. “For those people who really aren’t at risk … I would recommend that they not take it.”
The CDC said it’s unclear whether rebound symptoms have anything to do with Paxlovid, or are simply part of the natural trajectory of COVID-19. The agency did not flag any specific concerns about health effects.
“COVID historically has had this sort of stuttering course — people will feel better one day and then feel worse the next day, but I can say we haven’t seen these rebound symptoms with other COVID treatments,” said Vijayan, referring to therapies such as monoclonal antibodies.
The CDC on May 24 issued an alert to healthcare providers warning them about the rebound saying that patients who took Paxlovid could test positive for the virus after testing negative or can experience COVID-19 symptoms.
“A brief return of symptoms may be part of the natural history of SARS-CoV-2 infection in some persons, independent of treatment with Paxlovid and regardless of vaccination status,” the CDC said in an effort to “normalize” the relapses.
“Limited information currently available from case reports suggests that persons treated with Paxlovid who experience COVID-19 rebound have had mild illness; there are no reports of severe disease. There is currently no evidence that additional treatment is needed with Paxlovid or other anti-SARS-CoV-2 therapies in cases where COVID-19 rebound is suspected,” the agency added.
NIH investigating why people relapse after taking Paxlovid
The National Institutes of Health (NIH) said on April 29, they will investigate how often and why COVID-19 rebounds in some patients who complete a five-day course of Paxlovid.
“It is a priority,” Clifford Lane, deputy director for clinical research at the National Institute of Allergy and Infectious Diseases said. It’s “a pretty urgent thing for us to get a handle on.”
Lane said the agency is consulting with scientists at the CDC about conducting epidemiological and clinical studies to examine the post-Paxlovid relapses.
In response to reports of patients relapsing after taking Paxlovid, Pfizer CEO Albert Bourla suggested people are taking the treatment contrary to the established protocol. A U.S. Food and Drug Administration (FDA) official said Bourla’s comment was not true.
John Farley, M.D., director of the Office of Infectious Diseases, in the FDA Updates on Paxlovid for Health Care Providers wrote:
“There is no evidence of benefit at this time for a longer course of treatment (e.g., 10 days rather than the 5 days recommended in the Provider Fact Sheet for Paxlovid) or repeating a treatment course of Paxlovid in patients with recurrent COVID-19 symptoms following completion of a treatment course.”
Both Bloomberg and ABC News have reported on accounts of viral rebound after treatment with the drug. People described feeling better after starting the five-day course of Paxlovid, testing negative on a rapid test after treatment and resuming normal activities, only to have their symptoms come back within days of their final dose. Some patients even tested positive again.