Rare cases of COVID returning pose questions for Pfizer pill

As extra medical doctors prescribe Pfizer’s highly effective COVID-19 tablet, new questions are rising about its efficiency, together with why a small variety of sufferers seem to relapse after taking the drug.

Paxlovid has turn out to be the go-to possibility in opposition to COVID-19 due to its at-home comfort and spectacular ends in heading off extreme illness. The U.S. authorities has spent greater than $10 billion to buy sufficient tablets to deal with 20 million individuals.

However consultants say there may be nonetheless a lot to be realized concerning the drug, which was approved in December for adults at excessive threat of extreme COVID-19 primarily based on a examine wherein 1,000 adults obtained the medicine.

WHY DO SOME PATIENTS SEEM TO RELAPSE?

Docs have began reporting uncommon instances of sufferers whose signs return a number of days after finishing Paxlovid’s five-day routine of tablets. That’s prompted questions on whether or not these sufferers are nonetheless contagious and will obtain a second course of Paxlovid.

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Final week, the Meals and Drug Administration weighed in. It suggested in opposition to a second spherical as a result of there’s little threat of extreme illness or hospitalization amongst sufferers who relapse.

Dr. Michael Charness reported final month on a 71-year-old vaccinated affected person who noticed his signs subside however then return, together with a spike in virus ranges 9 days into his sickness.

Charness says Paxlovid stays a extremely efficient drug, however he wonders if it could be much less potent in opposition to the present omicron variant. The $500 drug therapy was examined and OK’d primarily based on its efficiency in opposition to the delta model of the coronavirus.

“The flexibility to clear the virus after it’s suppressed could also be completely different from omicron to delta, particularly for vaccinated individuals,” stated Charness, who works for Boston’s VA well being system.

May some individuals simply be inclined to a relapse? Each the FDA and Pfizer level out that 1% to 2% of individuals in Pfizer’s unique examine noticed their virus ranges rebound after 10 days. The speed was about the identical amongst individuals taking the drug or dummy tablets, “so it’s unclear at this level that that is associated to drug therapy,” the FDA said.

Some consultants level to a different risk: The Paxlovid dose isn’t robust sufficient to totally suppress the virus. Andy Pekosz of Johns Hopkins College worries that would spur mutations which are proof against the drug.

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“We must always actually make certain we’re dosing Paxlovid appropriately as a result of I might hate to lose it proper now,” stated Pekosz, a virologist. “This is likely one of the important instruments we now have to assist us flip the nook on the pandemic.”

HOW WELL DOES PAXLOVID WORK IN VACCINATED PEOPLE?

Pfizer examined Paxlovid within the highest-risk sufferers: unvaccinated adults with no prior COVID-19 an infection and different well being issues, equivalent to coronary heart illness and diabetes. The drug lowered their threat of hospitalization and demise from 7% to 1%.

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However that doesn’t replicate the overwhelming majority of People right now, the place 89% of adults have had at the very least one shot. And roughly 60% of People have been contaminated with the virus sooner or later.

“That’s the inhabitants I care about in 2022 as a result of that’s who we’re seeing — vaccinated individuals with COVID — so do they profit?” requested Dr. David Boulware, a College of Minnesota researcher and doctor.

There’s no clear reply but for vaccinated People, who have already got a hospitalization fee far beneath 1%.

That will come from a big, ongoing Pfizer examine that features high-risk vaccinated individuals. No outcomes have been printed; the examine is anticipated to wrap up within the fall.

Pfizer stated final 12 months that preliminary outcomes confirmed Paxlovid failed to satisfy the examine’s targets of considerably resolving signs and decreasing hospitalizations. It just lately stopped enrolling anybody who’s obtained a vaccination or booster prior to now 12 months, a change Boulware says suggests these sufferers aren’t benefitting.

At a minimal, the preliminary knowledge ought to be launched to federal officers, Boulware stated. “If the U.S. authorities is spending billions of {dollars} on this drugs, what’s the duty to launch that knowledge in order that they will formulate a great coverage?”

CAN PAXLOVID BE USED TO HELP PREVENT COVID-19 INFECTION?

Pfizer just lately reported that proactively giving Paxlovid to relations of individuals contaminated with COVID-19 didn’t considerably cut back their probabilities of catching it. However that’s not the top of the story. Pfizer is finding out a number of different potential advantages of early use, together with whether or not Paxlovid reduces the size and severity of COVID-19 amongst households.

“It’s a excessive bar to guard in opposition to an infection however I’d like to see knowledge on how Paxlovid did in opposition to extreme illness as a result of it might be more practical there,” stated Pekosz.