Los Angeles –
Use of Pfizer Inc.’s COVID-19 antiviral Paxlovid has surged this week, but some doctors are reconsidering the pills for lower-risk patients after a US health agency warned symptoms could return after people took a completed treatment with the drug and that they should then isolate a second time.
More quarantine time “isn’t a crowd pleaser,” said Dr. Sandra Kemmerly, an infectious disease specialist at Ochsner Health in New Orleans, told Reuters. “For those who really aren’t at risk…I would recommend not taking it.”
The use of Pfizer’s Paxlovid, approved to treat newly infected, vulnerable people to prevent serious illness, has surged as infections have risen. More than 162,000 courses were taken last week – compared to an average of 33,000 a week since the drug’s launch late last year, according to government data. Biden administration officials have been pushing for widespread use of Paxlovid, which the government bought and made available for free.
But higher use has also come with more reports from people saying their symptoms were relieved with Paxlovid, only to return a few days after stopping a five-day pill.
On Tuesday, citing case reports and concerns that relapsing patients could spread the virus, the Centers for Disease Control and Prevention issued its recommendation that Paxlovid users isolate themselves for an additional five days if symptoms recur.
“I shy away from giving it to people who are very low risk and not very sick, especially people who are vaccinated and boosted,” said Dr. Bruce Farber, chief of public health and epidemiology at Northwell Health. He said he still recommends Paxlovid for people with significant health conditions or over the age of 75.
Pfizer said in an email that it is monitoring the data but believes the return of detectable virus is unusual and not exclusively linked to its drug. “We have not seen any resistance in patients treated with Paxlovid to date,” said a spokesman.
Paxlovid’s emergency medical approval says it should only be used for newly infected people with risk factors, but doctors said many others had requested a prescription.
“We get a lot of requests – maybe someone is traveling and wants to take it with them just in case,” said Dr. Tara Vijayan, an infectious disease specialist at UCLA Health in Los Angeles. “We don’t offer it as a just-in-case.”
The CDC also said it’s unclear whether cases of rebound symptoms have anything to do with Paxlovid or are simply part of the natural trajectory of COVID-19. The agency has not raised any particular concerns about health effects.
“COVID has had this kind of stuttering history in the past — people feel better one day and worse the next day, but I can say we haven’t seen these rebound symptoms with other COVID treatments,” Vijayan said, relating focus on therapies such as monoclonal antibodies.
“The patients who get a rebound are usually very mild,” said Dr. Earl Strum, medical director for employee health at USC’s Keck Medicine in Los Angeles.
Some are wondering how much Paxlovid is helping given the high number of people who have been vaccinated or previously infected with COVID-19. The drug was approved in December after a study of unvaccinated, high-risk COVID-19 patients with conditions like diabetes showed an 88 percent reduction in hospitalizations or deaths.
At that time the Delta variant was dominant, but has since been superseded by the more transferrable Omicron.
“There is so much more baseline immunity. There are still a lot of infections, but they’re not nearly as severe,” Northwell’s Farber said.
He estimated the rate of Paxlovid-related COVID-19 rebounds to be about 10 percent — higher than the three to four percent rate reported by Pfizer in its studies of the drug.
Jason Gallagher, an infectious disease expert at Temple University’s School of Pharmacy, said the rebounds don’t detract from the drug’s usefulness. “It keeps you from going to the hospital … if you get symptomatic after you stop taking it, it stinks, but overall the drug has been a success,” he said.